Malaysia Airlines MH370 has been missing for more than 10 days, and everyone is still baffled about its whereabouts. The transponders were apparently deliberately turned off, and the plane continued "pinging" a satellite as it traveled up to seven and a half hours. A new theory suggests that it was shadow following another plane from behind to avoid detection.

One man has a theory that has gotten the attention of scores on Twitter — and spawned a full discussion on Reddit. The theory — neither slightly proven nor recognized as a possibility by officials conducting the search, to be sure — put forth by a 30-year-old aviation hobbyist, has started to make its rounds to offer a plausible explanation.

The theory suggests that the plane was able to escape both civilian and military radar detection by flying completely in the dark, and behind a Singapore Airlines plane with a route to Spain.

Keith Ledgerwood, who posted it on his tumblr  has taken a deeper look at some of the public data and found something that we haven't seen elsewhere before today.

He writes:
Starting with a set of facts that have been made available publicly and verified over the past few days, I first plotted MH370’s course onto an aviation IFR map which shows the airways and waypoints used to navigate the skies. I plotted the point where it stopped transmitting ADS-B information at 1721UTC. I then plotted the Malaysian military radar track from that point towards “VAMPI”, “GIVAL”, and then onward toward “IGREX” on P628 ending with where the plane should be at 1815UTC when military radar lost contact.
That map looks like this:

Ledgerwood found another Boeing 777 en-route from Singapore and flying high over the Andaman Sea: Singapore Airlines flight 68. It was traveling on the same path that Malaysian military radar had shown MH370 headed towards at precisely the same time, he says.

"It became apparent as I inspected SIA68’s flight path history that MH370 had maneuvered itself directly behind SIA68 at approximately 18:00 UTC and over the next 15 minutes had been following SIA68," he writes. "All the pieces of my theory had been fitting together with the facts that have been publicly released and I began to feel a little uneasy."

Singapore Airlines Flight 68 proceeded, without any knowledge of Flight 370 behind them across the Andaman Sea, into the Bay of Bengal, and up through India, Pakistan, Afghanistan, Turkmenistan, and its final destination: Barcelona, Spain (watch it here). MH370, if the pings are to be believed, wasn't all that far behind.
So by now, you may have caught on or you may be scratching your head and wondering if I’ve gone insane! How does SIA68 have anything to do with MH370 disappearing? Remember the one challenge that is currently making everyone doubt that MH370 actually flew to Turkmenistan, Iran, China, or Kyrgyzstan? That challenge is the thought that MH370 couldn’t make it through several key airspaces such as India or Afghanistan without being detected by the military.

It is my belief that MH370 likely flew in the shadow of SIA68 through India and Afghanistan airspace. As MH370 was flying “dark” without transponder/ADS-B output, SIA68 would have had no knowledge that MH370 was anywhere around and as it entered Indian airspace, it would have shown up as one single blip on the radar with only the transponder information of SIA68 lighting up ATC and military radar screens.
Ledgerwood theorizes that the plane was safely out of range of the radar systems in India, Pakistan and Afghanistan, and all the pilot had to do was simply "break off from the shadow of SIA68" and land at any runways, known or unknown, near Xingjian province, Kyrgyzstan or Turkmenistan.

Singaporean pilots had no idea what was tailing closely behind, as the TCARS system only works if it receives transponder information from nearby planes (and MH370's was off).
There are too many oddities in this whole story that don’t make sense if this theory isn’t the answer in my opinion. Why did MH370 fly a seemingly haphazard route and suddenly start heading northwest towards the Andaman Islands on P628? If not for this reason, it seems like a rather odd maneuver. The timing and evasive actions seem deliberate. Someone went through great lengths to attempt to become stealthy and disable ACARS, transponder/ADS-B (even though SATCOM to Inmarsat was left powered).

After looking at all the details, it is my opinion that MH370 snuck out of the Bay of Bengal using SIA68 as the perfect cover. It entered radar coverage already in the radar shadow of the other 777, stayed there throughout coverage, and then exited SIA68’s shadow and then most likely landed in one of several land locations north of India and Afghanistan.
Read the full theory over at Ledgerwood's tumblr. He continues to update it as more readers write him with more feedback. It sounds like the most plausible theory so far.