That appears to be a CH-53 Super Stallion, which can fly a maximum of 990 nmi (1,139 mi, 1,833 km) on a full tank. A C-5 Galaxy can fly 2,400 nmi (2,760 mi, 4,440 km) with a 263,200 lb (119,400 kg) payload. So if you need to move a helicopter a long distance, it makes perfect sense to put it in a cargo plane.

Also: Sup dawg, I heard you like aircraft so we put a helicopter in your airplane so you can fly while you fly!