The Helipad is a support structure designed to build, refuel and rearm GDI and Nod aircraft. Without it, the aircraft would be left without ammunition to perform any offensive role.
As the technology became more sophisticated, helipads evolved. In the Second Tiberium War, the weapons were much more complex and required longer reload times than their predecessors due to their integration within the frame of the aircraft at a greater level than previous generation gunships. Nod redesigned the original circular platforms, relocating the fuel tanks and weapon racks to the outside to allow swift rearming and refueling of Harpy assault helicopters and Banshee fighters, while GDI developed what essentially was a bunker with a helicopter landing pad on its top, which was compatible with most ORCA aircraft, this including Orca Fighter, Orca Bomber, and Orca Carryall. An unique quirk is that all type of helipad can reload ammunition onto any strike aircraft in position, regardless of the faction technology trees and aircraft assigned to them.
Each helipad can only serve one aircraft. If the structure is captured, the parking aircraft is captured as well. Interestingly, if every helipad is occupied, new-built aircrafts will appear from a random point on the edge of the map and fly directly to the helipad which is set as "primary", should an aircraft is "pre ordered". Field commanders can use this to reveal shroud even discover enemy bases but only in Tiberian Sun and Firestorm.