I have the same problem.
Few minutes after joining the game, I get "host connection lost" msg. I've just recently installed 2.13 AH , played with it for a bit and everything seemed fine. While in game when I try to change airfields or want to take off, there is few seconds of delay before game actually moves me to the other field or puts me in the cockpit. Other then, everything seems normal. I don't see any warping or any "lost UDP, switching to TCP" messages, net status bar is pretty solid without any spikes..
I'm running Vista, 8800GTX, etc. Cable Broadband connection. No router. No wireless.
Ran pingplotter, everything seems fine, altho on hop #1 it says 100% packet loss, not sure if that's causing the problem (read on some forums, that might be normal). All other hops are fine. I don't see packet loss on any other hops or some crazy spikes. There are also no red bars on the bottom of pingplotter screen.
P.S. I did change the textures to 512 as per Skuzzy's instructions (was also using hirestexture pack which was installed after 2.13 but before patch 1 i think). Problem remains.
Any help is appreciated.