Agree with emphasis: that the eTA will have no impact at all on the capacity of Canadian PRs to board a flight destined for Canada by displaying either (1) a currently valid PR card, or (2) a PR Travel Document.
In this regard, remember "Travel Document" is a generic reference to various types of documents which are used to show authorization to travel internationally. Passports are the most common form of "Travel Document," and some Travel Documents have a very limited function as a Travel Document . . . the Canadian PR card, for example, is a "Travel Document" but it is generally only valid as a Travel Document for traveling to Canada. Some countries might recognize it as a Travel Document, but most do not . . . thus, for example, many countries with exit controls will require travelers to show some Travel Document other than the PR card before being allowed to board a flight leaving the country.
Illustrative examples:
-- a passport which is not visa-exempt will not constitute a Travel Document authorizing travel to Canada unless there is a permit or visa or such affixed to or properly accompanying the passport which authorizes travel to Canada
-- single-use Travel Documents authorizing one specific instance of travel are common; the PR Travel Document is such a Travel Document, as it is only good for a trip to Canada
-- broader Travel Documents can authorize travel in lieu of a passport; for example, refugees who are Canadian PRs can obtain a Travel Document which will authorize travel to many countries in the world except the country of origin
Further attempt to clarify as to impact for short-landing Canadian PRs:
Foremost: short-landing PRs, that is, those who come to Canada in order to do the landing which makes them a Canadian PR, but who leave Canada soon before receiving their PR card (which can be as soon as almost immediately after landing), should have little problem obtaining a PR Travel Document to facilitate their return to Canada, so long as they do so less than three years after the date of leaving Canada (with enough of a margin that their travel takes place less than three years after the date of leaving Canada). This is what the rules technically require.
However, many short-landing PRs arrange to have the PR card mailed to a trusted person (family or friend), in Canada, who will in turn send the PR card to the new PR abroad (preferably using secure courier service).
Beyond that, historically many PRs who otherwise carry a visa-exempt passport have, in practice, used their visa-exempt passports for the purpose of the pre-boarding checks, pursuant to which boarding passengers are required to display a Travel Document authorizing entry into Canada. That screening is conducted by airlines (and other commercial transportation providers). This practice has not been limited to short-landing PRs who do not have a valid PR card due to leaving Canada so soon after landing, but has been engaged in by many PRs carrying a visa-exempt passport who otherwise, for whatever reason, do not have a valid PR card to display.
The flight-boarding scenario for Canadian PRs who carry a visa-exempt passport and who do not have a valid PR card is largely the same whether they are a short-landing PR or have been a PR for a long time.
What happens at the POE is a separate matter. Note that regardless of how it is that a returning Canadian PR gets himself or herself to the POE, once at the POE a Canadian PR is entitled to entry into Canada. Of course, the traveler must prove identity and technically also establish status, but proof of identity usually will also constitute establishing status. Nonetheless, it is always prudent for a PR without a valid PR card to otherwise have his or her CoPR to present at the POE.
The issue is typically more about being allowed to board a flight destined to Canada.
It has long been the rule that airlines (and other commercial transportation providers) must screen boarding passengers (boarding a flight destined to arrive in Canada) for a proper Travel Document which authorizes entry into Canada.
Thus, to board a flight destined for Canada, passengers have long been required to present one of the following:
-- Canadian passport
-- Canadian PR card
-- PR Travel Document
-- visa exempt passport
-- visa authorizing entry into Canada
-- other specific Travel Documents authorizing entry into Canada
Again, the airlines pre-boarding screening is separate and distinct from checks done at the POE upon arrival in Canada.
A Travel Document authorizing entry into Canada does not guarantee entry into Canada. That said, returning Canadians, including both returning Canadian citizens and Canadian PRs, are entitled to entry into Canada upon arrival at the POE. This is not dependent on the kind of Travel Document the traveler presented to the airlines or presents to officers at the POE, but is rather dependent upon establishing identity and status (as citizen or PR) at the POE.
Technically, in so far as the regulations are concerned, Canadian PRs have long been required to present either a valid PR card or a PR Travel Document in order to board a flight destined for Canada.
In practice, in contrast, many times a PR will display his or her visa-exempt passport to the individual screening for Travel Documents prior to boarding. The person doing the screening for the airlines is focused on (1) matching name/identity with the boarding pass, and (2) seeing that the passenger is displaying a Travel Document authorizing entry into Canada. (Note: how this is done will vary from country to country, somewhat from airline to airline, and it is worth remembering that many countries have exit controls which can be more thorough or restrictive.) Thus, the display of a visa-exempt passport has, typically, allowed the PR to board the flight . . . but technically the rule is nonetheless that the PR should have displayed either a PR card or PR Travel Document.
What is often overlooked is that in the meantime all flights to North America (to both the U.S. and Canada) involve security screening of passenger lists. Historically this appears to have been somewhat sporadic in its thoroughness, but has undoubtedly undergone extensive technological enhancement and as of today it is a fairly thorough check of all passengers destined for the U.S. and by some time next year will be likewise for all passengers destined for Canada. And this increasingly entails not just security screening but also status screening.
How it actually works in practice is NOT public information and will not be. We know certain aspects of what is done and how it works, but we do not totally know the extent to which boarding passengers are screened, either in security or status screening.
There has been a great deal of speculation about the impact of the eTA system for PRs with visa-exempt passports trying to travel to Canada using their visa-exempt passport rather than displaying a valid PR card.
Some of what we do know (or perhaps emphasizing what we do NOT know) re changes due to the eTA:
The eTA is now available. It becomes mandatory for all travelers next year, but now travelers with a visa-exempt passport can go into the system and obtain the clearance. This will be good for five years. So once the eTA has been obtained, it does not need to be done again, for up to five years, so long as that passport remains valid.
Thus, I expect some anecdotal reports in the near future from PRs who attempt to obtain the eTA using their visa-exempt passports. In the meantime we can only GUESS how this will go. CIC is not divulging, and will not divulge any more detail than the rules, and the rule is that a PR returning to Canada is supposed to display a valid PR card or a PR Travel Document in order to board a flight destined for Canada. Which again has been the rule for a long time despite the extent to which scores and scores of PRs have done otherwise (by presenting a visa-exempt passport instead).
My sense, my guess is that the eTA is (or in the not-so-distant future will be) tied to data-base processing which will automatically screen passengers whenever they travel on a flight destined to Canada, even after initially obtaining the eTA (that is, while the primary screening process is done attendant obtaining the eTA initially, that this will establish a client identity, or connect the passport to an existing client identity, which will be electronically screened every time that individual is listed in a Canadian bound flight manifest). But this really is a guess. My strong sense is that the systems will continue to expand and be more integrated, facilitating a great deal of electronic monitoring and screening of travelers, with criteria for issuing alerts/flags or such.
Part of what we do not know, assuming there is such greater robust screening (after initial eTA; denial of eTA due to a flag will require clearing the flag before the eTA is granted) for all passengers listed in a flight manifest, is whether or not alerts or flags will prevent boarding (at least until cleared) or will be in effect left for POE screening (obviously, certain types of security flags will indeed, as they do now, preclude boarding).
The big question for PRs is whether the electronic screening includes criteria to identify visa-exempt travelers who are Canadian PRs, and if so what it then does. Anyone proffering an answer to this question is guessing and guessing in the dark.
That said, the obvious direction things are headed is that sooner or later PR status is likely to be part of the screening.
That is, regardless of how it works next year, or in 2017, eventually PRs attempting to board a flight destined for Canada can anticipate having to present either a valid PR card or a PR Travel Document, regardless of what passport they carry (albeit it may be much, much longer before those carrying a U.S. passport run into this . . . remember the eTA requirements, for example, will not apply to U.S. citizens for the foreseeable future). We can only guess how soon this will happen.