Why does the 262 not preform well at altitude? Just too high a wing loading, like the 190, or do the engines not like the thin air?
262 starts getting dicey above 20k, where some late war piston engine fighters actually gain an advantage from acceleration and climb rate as well as speed. Late war aircraft like the Spit 14 and P51 can give you rather a problem at this alt.
Its climb rate drops off, as well as speed - if you are not careful you can easily get "caught". I was in a gaggle of 38s, 51s and 47s at 28k in a scenario - you do have the advantage of speed which is the only thing I had, then again when a flight of Spit 14's showed up I bugged out rather quick.
Below 20k the Me 262 has all the cards in every way, although it gets tougher really when you go above 15k, below 15k the Me262 is rather invisible if flown correctly.
On the deck it should not be shot down unless it gets bounced.