Aircraft sales and maintenance are milestone businesses

Charter takes money for a flight. Aircraft sales and maintenance take money across months, in stages, against work that is partly complete — and those are different payment problems that often sit inside the same company.

The stages, and who is exposed at each

• ·Deposit to hold an aircraft or schedule a slot. The customer has paid and received nothing.
• ·Progress billing as work proceeds. Both sides are partly exposed, which is the point of billing this way.
• ·Parts, which may be ordered specially and are hard to return.
• ·Completion and inspection, where disagreement about whether work met specification usually surfaces.
• ·Final delivery, after which the customer has everything and the merchant's exposure ends.

Why a generic checkout fails here

A single charge cannot show which stage it belongs to. When a dispute arrives over a $180,000 refurbishment, the question is never whether money changed hands — it is which milestone had been accepted and what was still outstanding. If every payment looks identical in the record, that question has no answer.

Payments tied to named milestones with customer acknowledgment answer it before it is asked, and they also make progress billing intelligible to an acquirer who would otherwise see irregular large charges with no pattern.

Maintenance disputes are rarely about fraud. They are about scope, and scope is a documentation problem long before it is a payment one.