Though some understand the rationale, corporate travel buyers don't like the new American Express Global Business Travel surcharge on certain airline bookings.

Concerns go beyond the amount of the fee, which client communications indicate is $10 per transaction. Customers raised several other financial and operational questions. Speaking anonymously due to the sensitive nature of supplier relationships, some GBT clients said they are considering recourse.

A few said they expect the hit to be tens of thousands . . .

The full content is available to subscribers