"Warning: this flight starts and ends in different airports"
Jesus christ, I'd forgotten how goddamned stupid airline websites are. One site expired my session twice and was clearly not expecting people to buy flights from outside the US. Another site said "warning: this flight starts and ends in different airports". The same flights were wildly different prices on aggregation sites, which seemed to be determined to sell me 9 hour flights starting at absurd times in the morning when a 4 hour flight would get me in sooner.
Argh!
Argh!