Yep. There are at least a couple of very, very good reasons civilian aircraft don’t fly formations.
1) It’s dangerous. There is absolutely no reason to be that close to another aircraft increasing the odds accidental collision.
2) You start risking destabilizing the following aircraft due to wake turbulence. Sure, if you are talking about two large passenger aircraft the one in the back “probably” won’t get flipped over or anything but... things happen. You don’t go looking for ways to mess up the wing’s function and a stable flight envelope in the name of saving a few gallons of gas.
We take commercial air travel for granted on a massive scale. It’s as safe as it is exactly BECAUSE every little thing the aviation industry does for safety all add up to one very safe overall experience.
Start taking away a few here and a few there and soon the accident rate will go up.
Planes fly 1 mile horizontal and 1000 feet vertical for a reason and it is the law. Two or three jets flying a formation would have to be closely computer controlled. Passenger jets would not be safe. Freight jets would be a different story. When jumbo jets started flying some small planes were knocked out of the sky by turbulence. Think what turbulence a formation of these guys would cause.
Not to mention the cluster-”blank” when both planes land at their destination.
Not to mention a rough ride.
Flight 587 from JFK went down from wake turbulence, or the pilots’ handling of that turbulence. 260 people died.
I suppose this proposal suggests reaching formation at a much higher altitude, and expecting and being prepared for any turbulence.
Wake turbulence is a substantial problem to overcome.
Also, different aircraft with different weight loads will react differently to the same patch of atmospheric turbulence. Some more intense than others. This greatly increases the safety risk for collision. Formation flying by the military generally avoids this risk since formations consist of same type of aircraft with each having nearly same weight.