This post originally appeared in Business Insider.

Not surprisingly, the disappearance of Malaysia Flight 370 with 239 people on board more than a week ago has led some people to come up with very interesting theories about what might have happened.

On his Tumblr, self-identified hobby pilot and aviation enthusiast Keith Ledgerwood put forward the most elaborate and interesting suggestion we’ve heard yet.

He argues the 777 could have flown over India and Pakistan, avoiding military radar detection by turning off its communications systems and following a Singapore Airlines 777 so closely the two aircraft “would have shown up as one single blip on the radar.” In his blog, Ledgerwood established that the Singapore Airlines flight was in the area.

The collision avoidance systems installed on all modern airliners operate using the transponder, which someone on the Malaysia flight could have turned off. So the Singapore crew wouldn’t have detected a plane on their tail, Ledgerwood speculates.

“Once MH370 had cleared the volatile airspaces and was safe from being detected by military radar sites in India, Pakistan, and Afghanistan,” Ledgerwood writes, “it would have been free to break off from the shadow of SIA68 and could have then flown a path to it’s final landing site.”

We asked Michael G. Fortune, a retired pilot who now works as an aviation consultant and expert witness, if that would be possible. After a lengthy pause, he gave us a skeptical “maybe.” It would depend on what kind of radar equipment the Singapore 777 had on board, he said, and would require some serious aviation skill to find and stay behind the plane.

Doug Moss, a former test pilot and aircraft accident investigator, was unconvinced. “It sounds totally crazy,” he told us, adding, “I see where the guy is coming from.” It’s possible in theory, he said. Large military planes can fly in formation, and there’s no reason one 777 couldn’t closely follow another.

“The hard part in practicality is, how’s the guy gonna find another airplane,” and especially a specific plane, headed to the right part of the world? Moss asked.

Like Fortune and Moss, we’re not convinced by Ledgerwood’s theory, but it is interesting to think about.

See also: The Missing Flight Could Be Anywhere in This Giant Circle