Follow the Leader
The idea behind "Follow the Leader" is to fly agile planes along a river and fly through the bridge supports or the bridge itself. Every person follows single-file through the run. The person in front determines what the rest of the team does. Whichever support they fly through (and at what speed), the rest must follow suit. If the leader does a perfect loop under the bridge, so too must everyone else. If the leader crashes, the next person in line becomes the new leader. Win conditions could be how long one remains the leader, who has the least crashes, or last plane flying. This works best with the realistic flight model, but can work just fine with arcade.
"Trench Run" would be very similar to "Follow the Leader" except that it follows more the classic Star Wars Death Star trench run. Effectively this would be "Follow the Leader" with enemy planes in pursuit. A few friendly planes would fly down the river with a few enemy planes firing at them. The friendlies would have to avoid the gunfire while also ducking and weaving through the bridges. The enemies would also have to follow the friendly planes through each turn, each support, each evasion. Win conditions would obviously be which team remains alive at the end of the run.
Some modifications to this idea could be the occasional strafing runs (from both teams on their opposites) and, if possible, the addition of tanks along the river.
So let me know what you all think.