Only six of the 71 combat missions were flown above 20,000 feet altitude.

Then, at 150 feet altitude, the Gazelle came to a halt, supported by its antigrav fields.

The bombers began their long torpedo runs at 800 feet altitude, and two were lost before they could release.

They are found mainly above 6000 feet altitude and up to 10000 feet in summer.

Meanwhile, another person in the National Airport control tower reported seeing "an orange disk about 3,000 feet altitude."

They did, and at two thousand feet altitude he pressed the button.

Even though the winds were not as strong lower down, Duncan maintained his 41,000 feet altitude so as to save fuel.

The third test was without oxygen at the equivalent of 29,400 feet altitude conducted on a 37-year-old Jew in good general condition.

A moment later the copter reappeared off to the side at about fifty feet altitude.

The two of them circled downwards to less than 1,500 feet altitude.