Plain English Meaning
The 'A' in PAVE asks: is this airplane up to this flight? Is it in good shape, equipped for what I'm about to do, and able to handle the weight, runway, and conditions I'll meet today?
Full Definition
In the PAVE checklist, the 'A' stands for Aircraft and refers to the pilot's preflight risk assessment of the airplane itself. This includes whether the aircraft is airworthy, properly equipped for the planned flight (day or night, VFR or IFR), capable of carrying the intended load, suited to the runways and terrain involved, and within limits for the expected conditions.