The Hornet and the Chopper should definitely return. The Hornet was the perfect air vehicle. It was fast and agile enough to dodge incoming projectiles. It wasn't overpowered with its missiles and chainguns as it wasn't very though and could be brought down with not too much effort. I cannot understand why this brilliant vehicle was removed.
The Chopper was a marvellous piece of work. It wad swift and was easily manoeuvrable. Its weapons were great and very effective against the Warthog. Bungie did a good job at giving this vehicle pros and cons. The feature of slow reverse and instant destruction when stuck really were clever. Yet another vehicle that should not have been removed.