Air France-KLM
Flying Blue status is earned on Experience Points (XP) over a 12-month qualification period that starts when you first qualify: XP come from every Air France, KLM and SkyTeam flight, weighted by cabin and distance. Air France and KLM are SkyTeam founders, so Gold and up is SkyTeam Elite Plus. Confirm current XP thresholds on flyingblue.com.
5 rungs, from the bottom up.
Qualification thresholds are the published ones as last checked and change most years; confirm the current numbers with Air France-KLM. Alliance equivalences and the lounge rules that follow from them move far more slowly.