the.com/ground crew

means The airport staff who fuel, load, inspect, and otherwise prep an aircraft between flights, handling everything that happens while it's still on the tarmac.

from A straightforward compound: 'crew' has meant an organized team (originally a ship's company) since at least the 1600s, borrowed from French recrue, 'reinforcement' — troops raised to fill out a company. 'Ground' was tacked on once aviation needed a way to distinguish the people who stay earthbound from the ones who fly; 'ground' itself just comes from Old English grund, solid old Germanic vocabulary for the earth beneath you. Put together, the phrase is as literal as it sounds — the crew that works the ground, not the sky.