Major Differences in Carrier 777 Coach Configurations (# of seats across)
I just flew a Turkish 777 in coach, having flown an Alitalia 777 in coach a few years ago in which I felt more cramped.
Turns out there are major differences in 777 coach comfort as many airlines squeeze in an extra seat across.
Quick look on Seatguru, here are some airlines that have 9 seats across (3 + 3 + 3) on 777 coach: KL (two different configurations, one with 10, one with 9), DL, UA, TK,
And some with 10 across (3 + 4 + 3): AZ, AF, KL (two different configurations, one with 10, one with 9), EK, AA.