I went to land while flying with my Elytra but upon hitting the ground i became stuck in fly mode. I removed the Elytra but was still able to fly 2-3 block of the ground as if i was still running with the Elytra equipped. While in this state I was able to equip a chest plate while remaining in fly mode.
http://imgur.com/RyBar1E
http://imgur.com/daxbYMh
http://imgur.com/oQe4Hh7
You can also clip into the ground while in this state
http://imgur.com/dBr2pG5