Ah okay - sorry about that! Thanks a lot for all the detail about how it happened. I'll do my best to track down the bug and fix it!
I'm having a similar problem, the first plane didn't trigger until I got reeeeeally close to it (I spent ages wondering why I couldn't move on and came back to the page to see if anyone had an answer - which is the only reason I tried to get really close to the plane, because i'd already tried to itneract with it heaps of times but I was clearly too far away) and after that nothing seems to be appearing or reacting. I'll have another go sometime (I don't really feel like replaying through it all again right now) and hopefully it was just a one-off bug, but it definitely happened to me too!