Seems to me that there are plenty of options for people looking to fly Jets.
I bought a share in a JP5 which was fairly cheap and it outperforms the L39 and it has oxgen so can get high.
L39 costs a little more but it feels good and I think it looks way better than the Jp.
Perhaps it is not as fast as a real fast jet but I got from North Weald to Elvington (York) in 27minutes and North Weald to Kemble in 17minutes and 15secs so it seems fast enough for me.
I beleive there are some shares in a Hawk at kemble and probably a Hunter as well.
Buy the shares, Fly the jet until you've had enough, Sell the shares.
Too expensive ???
Phone a friend who has one and ask him or a ride.