Bee stops flying if it cannot pathfind.

If you lock a bee inside blocks it will reach the highest block and stop flying, like literally the animation will stop and the bee will freeze there.

https://www.youtube.com/watch?v=8P03d3H1-_A&feature=youtu.be

 

If you set blocks above it will stand still on the ground and won't reach the top of the block plus you can see it's trying to fly for a while..

https://www.youtube.com/watch?v=6AXoCyMho4s&feature=youtu.be