Mythbusters already tested this and showed similar savings.

There are at least two competitive sports that I can think of that are directly based on the drafting concept: first one is peloton groups in long distance bicycle racing, second is Jr Johnson's drafting technique in Nascar stock car racing. In 1899 Charles "mile a minute" Murphy set a 60 mph speed record on a bicycle by drafting behind a train on tracks that had the ties smoothed over by 1 mile of plywood.

A rare instance I agree with military thinking!

the problem i see is the safety aspect
birds are feathery and pliable and can even survive mid airs !!! and they can all take off simultaneously
Multiple plane formation flights on the other hand would have to be marshaled and synchronized .
I .e. form up before setting of for their destination or meet up at some point in the sky to benefit from vortex surfing if they share a destination. The logistics and effort might outweigh the cost savings. I certainly would be an even more very nervous and anxious passenger watching this practice from my window while flying panayis zambellis luton uk

The lead goose doesn't do all the work. The job of leader is rotated among the members of the formation. I wonder if the lobsters trade the lead spot?

Would this work for wind turbines as well?

Did some work on a sail design back on 2003 specifically designed to take advantage of vortices. Used the IBFV flow modeling software from Jarke van Wijk at Eindhoven UNI then did some wind tunnel testing of a rough prototype at Auckland Uni with some positive but inconclusive results. Personally I believe higher velocities are required in the 20kts + range. My modeling predicted a vortice should form approx 4 meters directly ahead of a full scale version creating very substantial additional lift. Needs more work anyone wants to take a look the drawings are on my Facebook page back in 2003. https://www.facebook.com/christoalnz

Why is this news? This has been known for many decades - there's a reason why WW2 planes flew in the formations they did.

Would this principle be more or less fuel efficient than the utilization of ground effect by WIG craft,like the "Caspian Sea Monster"?

Have seen this principle exploited by wind turbines in Utah canyons. On the lead bird working harder: this is true but it also the case that it is not working as hard as when flying alone, just as any one who rides in close peloton groups when cycling can tell.