how do I do this in free flight?

Best way I can think of is get into the Goose (assuming you have the Deluxe version) which is amphibian and starts out on wheels. Fly it to the nearest body of water and land. Change airplanes into the Beaver and save the flight.

Or I'm sure you could pick a seaplane airport from the scenery if you knew where to go.

How do I change planes once i land??

Press Alt. This brings up the menu bar. Click on "Aircraft"/select aircraft.

Id recommend picking the aircraft you want to fly, then press the Y key and slew it to water.press Y again, and fly normally.

You can also search on airports for Water, or somthing similar.

Beerbadger

help wrote:

How do I start on water? I usually fly the beaver but always end up on a runway... and the beaver is on floats. how do i start on water instead?

some airports have water runways for example when selecting airports try serching united states, washington, friday harbor then the third one on the list should we the water one and should say W33 under ID (you could also just serch buy airport id) then if you go into choose a runway you should see that the runways say (water) beside the runway #