Especially considering that the longest successfull effort by a military sniper in the real world was only about 1.5 miles, 2430 kilometers, by Canadian Cpl. Rob Furlong, and it took three shots at a stationary target to get the job done. One clean miss, one hit the guy's knapsack, the third gutted him like a trout.
That shot beat the 2,250 m previous record shot by U.S. Marine Gunnery Sgt. Carlos Hathcock during our second place effort in the Southeast Asian War games.
Of course those were on man sized targets. Hitting a stationary aircraft at 4 miles *might* be possible, but you'd end up with an airplane with a half inch hole, one each. Of course if it was stationary, you could shoot again. Hitting something vital, say the engine core, would be, well, hit or miss.