planes had to fly at lower altitudes, placing themselves

Very low flyover height, lower than surrounding obstacles;

Very low flyover height, lower than surrounding obstacles.

Very low flyover height, lower than surrounding obstacles;

Horus, design of a sports hoverbike flying at very low altitude

We were having dinner and a plane flew over at a very low altitude.

We were having dinner and a plane flew over at a very low altitude.

Australian Army pilots train to fly at extremely low altitudes

The Roland system is effective against air threats from extremely low to medium altitude.

France : Manoir St Pol Roux the Magnificent at very low altitude!

An M551 Sheridan being dropped from a C-130 Hercules.

This pair of glaciers is unique owing to its low altitude.

The birds were flying so low, almost touching the water.

It is flying at a very low altitude which is very strange for a normal airplane.

Their purpose was to defend against high and low-level air attacks.