There are some skin related bugs tonight.
The Soviet IL-4 skin for the Betty does not work, sadly. It could not be baked in as the default without causing a game crash.
Also, it seems that something in the SEA1 arena isn't liking today's skin update.
Problem 1: You may not see any skins at all on the list. In this case, exit the game completely and relaunch it. Go to the MA first and wait a few minutes for the skin roster to populate. If that does not work, you'll need to delete the "skins.res" file from the skins folder in your AH directory. Then relaunch and go to the MA. Only after getting the skins to show in the MA will they work in SEA1.
Problem 2: None of the new skins will work in that arena even if you can see them in the MA. You will get an "Invalid skin number" error message. Or you will not see the new skins at all in the list. There is no fix for this without HiTech making some repairs.