When i flew the La5 for a tour the lack of range really got my goat. It's great for base defence, etc. but you can't go scouting around looking for trouble much.
However, if when you get up to alt, you look around and the sky is empty, reduce your rpm to just over half, throttle back to two-thirds and you can stay up there at about 150mph for a lot longer. (sorry i can't remember any exact values, it was a few months back) This is actually a far more realistic way to fly, just make sure you have plenty of alt so that you can accelerate down on any cons. (and don't forget to max out rpm and throttle again)
Of course flying at alt is less than ideal in an La5, but it's still a damn good plane even at 20k+.
At the moment i fly the P38 and zenos (
http://www.zenoswarbirdvideos.com/main.html) has charts for rpm and manifold settings to maximise range. At combat power, 2600rpm, 44inches Manifold, 314mph at Sea level, fuel consumption is 245 gallons per hour. At maximum economy the figures are 1600rpm, 22" Manifold, and 161mph at sea level for a fuel consumption of 46 gallons per hour! obviously in AH we don't have control over everything such as mixture, but by dropping your rpm's and lowering manifold a little, you can really extend your range.
