@stifle : from my past 2 flights to/above the USA, I was delayed around 45-50 minutes while they would make their "phone calls to clear me", not to mention the time which I got SSSS. I planned my connections accordingly, but I don't want to be wasting 50 minutes at each layover. This is why I want to be checked all the way through.
Can AC call the UA or HA head office for clearance , or does each airline only call their own head office?