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I have a roundutrip planned from Sydney to Los Angeles. I think the easiest would be to get an ESTA on my Australian passport and just travel on that passport alone. But I'm looking to avoid this if possible as I would rather use my Canadian passport to enter the US (no fingerprint… eye scan; may get preferred line at immigration; no ESTA fee or application).
I have valid passports for both countries (identical personal information, name, dob). Australia rules suggest that I must leave/enter Sydney with my Australian passport. From reading dual citizenship posts on this website, it seems an ESTA may not be needed on for an Australian passport.
Departure flight: I can check in with the airline (Delta) in Sydney with my Canadian passport, then proceed to immigration and leave with my Australian passport. I enter the US at LAX with my Canadian passport. For the return flight: at LAX, I should check in with the airline with my Australian passport (even though I don't have an ESTA) to show I have status to return to Australia, exit at US customs on my Canadian passport (because I entered the US on that passport).
Is it ok to travel without an ESTA on an AU passport even though I will need the AU passport at LAX to fly back to Australia?
Will the new smart gates used at airport security/immigration allow passage if the airline ticket and country of passport do not match (ie in Sydney having checked in with the airline with my Canadian passport but use the Australian passport at smart gates or vice versa at LAX)?