The answer first

Flying Blue members can request a travel-class upgrade after booking, including to Business if the flight and offer allow it. Before check-in opens, KLM lists Miles as the only payment method. After check-in opens, cash and Cash & Miles are also listed. Upgrades remain subject to availability; this guide does not identify a bookable seat, price or flight.

Before or after check-in: payment changes

Before check-in, KLM lists online or phone requests paid with Miles only. Once check-in opens, it lists Miles, cash or Cash & Miles and adds airport requests. Onboard requests are described only for Air France and KLM flights. Waiting for the option to pay cash carries a risk: an upgrade seat may no longer be available.

The operating airline matters

For Air France, KLM, Aircalin and Delta-operated flights, KLM describes advance upgrades until check-in opens. For other SkyTeam-operated flights, it says up to three days before departure, subject to availability and conditions. On a connecting booking, check the operator and cabin of each segment rather than relying on the marketing brand on the ticket.

What if the ticket is already an award?

KLM says reward tickets can also be upgraded, but only after check-in opens and subject to availability. Miles used for the original award do not automatically include a higher cabin: treat the upgrade as a separate decision with its own terms.

A better seat does not buy more XP

XP continue to be calculated from the original booked travel class even if you later sit in a higher cabin. Miles connected to the upgrade are earned only on the portion paid with a method other than Miles. KLM says lounge access, priority boarding and seat options may be included. Check what the actual offer provides instead of assigning a guaranteed cash value to unconfirmed benefits.

What to check before accepting

Teaching example: for Rome–Amsterdam–New York, open the booking and check which segment has the upgrade, its operating airline, new cabin, Miles and/or cash cost, and the listed extras. Then compare the total with a Business ticket bought directly for the same flights and conditions. Without actual quotes, no saving has been demonstrated.

Cash or points?
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October 1, 2026

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