Board Thread:General Discussion/@comment-26183061-20150601033259/@comment-26183061-20151025054453

Update: Got the extra slot, bringing the total to 40, and then upgraded it to Lv15, which added another slot, bringing the new total to 41. Game says no more expansion slots will be awarded, as they are now maxed out. Theoretically, there will be one more slot at Lv20 when Bamco uncaps the level limit to allow this plane to level up that high.

And yes, 41 slots and all those 6AAM and QAAM was worth it. :)