Block Hour

A block hour measures elapsed time from when the aircraft first moves under its own power ('off blocks') to when it stops at the destination ('on blocks') — so it includes taxi time, not just airborne time. Charter and operating costs are usually reckoned per block hour or per flight hour, so it pays to know which a quote uses.

Why it matters: block time runs from the moment the aircraft first moves under its own power to the moment it stops at the destination — taxi included. It is the standard unit for crew records, many maintenance programmes and most commercial billing, so knowing what is being measured matters whenever hours are being counted or charged.

The practical detail is the gap between block time and airborne time: at congested airports, taxi can add meaningful minutes per sector. When comparing charter rates or budgeting programme costs, confirm whether the hourly basis is block or airborne — across a year the difference is real money.