Originally Posted by
eponymous_coward
Why would you drive across NYC during rush hour with a fairly small margin of error for making your flight (YYJ-SEA-EWR on AS/JFK-TLV on DL), instead of just redeeming YYJ-SEA on AS/SEA-JFK-TLV on DL?

Heck, you'll even end up in the same concourse at SEA (I think the QX Canada flights come in in S).
It was just suggested as an option if nothing better was available. And EWR to JFK is very "doable" by shuttle since @530 at least from EWR to JFK you'd be going in the opposite direction of most rush hour traffic.