airline · 1 tier tracked · 1 free way in, 0 conditional
The only route to Flying Blue Silver runs through the Air France-KLM Visa Signature card, which carries an $89 annual fee. Spend $3,000 in the first 90 days and the welcome bonus delivers 100 XP plus 70,000 miles — since Silver only requires 100 XP, that spend alone puts you at Silver instantly.
Keeping Silver after that first year doesn't require a fresh application. The card earns 20 XP automatically on every account anniversary, and spending $15,000-$24,999 in that anniversary year adds an 80 XP bonus — together that's exactly the 100 XP Silver needs, so card spend alone can maintain the tier indefinitely. Push spend to $25,000 or more and you pick up 60 additional XP, for a maximum of 160 XP a year from the card. That's still short of the 180 XP Gold requires, so Gold isn't reachable through this card by spend alone — the card gets you to Silver and keeps you there, nothing higher.