Called HIFR (helicopter in flight refueling), it is done all the time, especially by Navy helos who can do it from ships without decks, or do not want to take the time for a deck landing, or to keep the deck clear. It takes specialized fittings and training, the hose is passed to the hovering helo, and the crewman fastens it . The fitting is usually placed near the door for ease.
Here is a Sea King, Lynx and Sea Hawk
In flight refueling of helicopter from USS De Haven
http://www.ussdehaven.org/images/and...es/image45.htm
http://home19.inet.tele.dk/sobertow/...riton/Hifr.jpg
