HONOLULU - The desperate search for five marines missing after a mid-air refueling accident off the coast of Japan, comes amid an alarming rise in the number
 of accidents involving U.S. military aircraft.

The search was hampered by strong winds and low visibility.

The F-18 fighter was attempting to refuel in the middle of the night with the massive KC-130 tanker -- which is essentially a flying gas station -- when the two airplanes collided midair.

The refueler has retractable hoses with baskets on the end. The fighter jet must approach the refueler from the rear and below, and plug its own retractable nozzle into the moving basket --all of this mid-flight. The two aircraft are within about 20 or 30 feet of each other, using night vision goggles.

"Although the F-18 has radar, it's night, you have no visual horizon, it's a dark sea underneath you, and visual illusions are easy to mistake, especially when you're trying to rendezvous close on another airplane," said one official.

The two marines who were found yesterday -- one dead and one alive in the fighter jet.

There is growing concern about the frequency of accidents in the U.S. military. A Military Times Report found that in five years -- the accident rate for U.S. warplanes has climbed nearly 40%.