Hans Loudermilk, a California man with ties to a Bangkok school has been jailed on charges he molested and sexually propositioned 15-year-old girl while seated next to her on a Delta Airlines flight from LA to Salt Lake City on March 26.

According to an FBI affidavit published by The Smoking Gun website, 66-year-old senior spotted the child, identified in the affidavit as only "KD", sitting alone and asked her to move to the middle seat.

The pair began chatting innocently at first but it quickly took a sexual turn as he began stroking her chin. The girl says he said he could teach her about sex the way a schoolboy couldn't. He allegedly began stroking her thigh and told her the pair could marry in Utah, the state they were landing in.

As soon as the plane touched down the girl found a TSA agent and told him of the ordeal. When Louderman spotted the pair talking he raced into a gift shop to change his shirt in the hopes of getting away unmolested.

Loudermilk's Facebook page shows an apparently single man who photographs and makes off-colour comments sexual about women he doesn't know. According to commentary on one such photo, it seems even his daughter in uncomfortable with his behaviour.