Starjets B737-800 American 'Astrojet' N951AA [Chrome] 1:500**Discontinued**
The glue holding the box together has dried out & the box can be unfolded. This is a common occurrence & we are routinely gluing boxes back together. 1/200 Gemini A380 boxes frequently fall apart, as do some of their B777 boxes [ I just put one back together ] because they are made with heavier board than typical 1/200 Gemini models. You can run a bead of white glue along the flap, secure it with elastic bands & let it dry overnight- that does the trick.
 Stuff ages folks, with glue being among the first things to fail over time. I was gonna glue this box together & have done with it, but then I noticed the lovely Chinese factory script inside the flap & decided to let it be. You can fold up the box & it still maintains it's integrity. You make the decision.