On any creative world last used in 0.15.6 the players starts in survival. You can easily change it to creative but I would expect this to default to the default game mode of the world not just survival. The main reason this is bad is that if you saved flying you die due to a fall, mobs (specifically creepers) become hostile and attack, ect.
MCPE-16907
Gamemode always starts in survival on creative worlds from 0.15.x
Resolved
Cannot Reproduce
0
(Unassigned)
Unconfirmed
Tablet - Android - Samsung Galaxy Tab 4 Nook
5.0.2
0.15.90.2
Retrieved
This is a bulk resolve of issues that haven't been updated to 0.16.0+ yet. Please comment below (To open the ticket) and update your affected versions. If you cannot reproduce the bug, please write in the comments so we can resolve it as "Cannot Reproduce". Thank You!