I have no experience, so don't take my word too seriously, but...
in my opinion, the basketball will not pop as the change in air pressure in the pressurized passenger cabin isn't that great. The basketball skin is pretty thick.
Violins, when travelling on airplanes, usually have their "E" strings loosened a little as that may pop, but usually all my string come out fine even when I forget to do anything. I'm not even sure if the string pops because of air pressure or change in temperature.
But as I said, no guarantees here!