Airborne force - Airhead

Japanese: 空挺堡 - くうていほ

...When supplies and logistical facilities can be accommodated, the crossing operation is completed, and the bridgehead is completed (usually 20 to 30 km deep). Similar terms include airhead and beachhead. In airborne and amphibious operations, the first troops secure airfields and landing beaches for the main forces to move on to later operations.

From [Airborne Operations]

...Airborne operations involve specially organized and trained forces, who, in cooperation with air units, carry considerable heavy equipment, move quickly over long distances, parachute or make a forced landing in enemy territory, and secure key points within the objective area. These positions are called airheads. These objectives are usually selected on the enemy's flanks and rear, so they pose a great threat to the enemy. ...

*Some of the terminology that refers to "airborne fort" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…補給品，兵站（へいたん）諸施設が収容可能になり，渡河作戦が終了し〈橋頭堡が完成された〉という(通常20～30kmの縦深)。類似語としては空挺堡airhead，海岸堡beachheadがある。空挺作戦と上陸作戦の場合の用語で，先遣された部隊が後続主力のために，事後の作戦に移行するための飛行場や揚陸海岸を確保することは同じである。…