flight ceiling

The highest altitude at which an aircraft may fly due to physical factors, such as low air density.

Japanese Meaning

物理的要因（例えば、低い空気密度など）により、航空機が飛行可能な最高高度。

The new turboprop reached its flight ceiling sooner than expected, forcing the crew to plan a lower-altitude route.

その新型ターボプロップ機は予想より早く最高運用高度に達したため、乗務員はより低い高度の航路を計画せざるを得ませんでした。

Sense（1）

The highest altitude at which an aircraft may fly due to physical factors, such as low air density.

flight ceilings

（ plural ）