How do you determine who CHOSE the flights then,?
In general, what typically determines this is "Who's got your money now?" If the
travel agent is holding your money, they're responsible for getting you to Orlando or refunding your money. If they've purchased your airline ticket for you and so the airline has your money, then they're typically not legally obligated to get you to Orlando if the flight is cancelled or the airline ceases operations (though they may be willing to help you, of course).
There are some indicators of this which you can look for. First, did you pay a deposit for the package PLUS the airfare? If so, then it's probably the latter situation, above. If you just paid a deposit for the package, and that deposit was actually less than the airfare, then it is almost surely the former situation, above. If you just paid a deposit for the package, but that deposit was significantly more than the airfare, then it is inconclusive.
Another indicator would be the the terms and conditions of your package. If it says that the travel agent can change flights without your authorization then they're clearly responsible to get you to Orlando, no matter what, or refund your money.
Another (though less reliable) indicator is how pricing is listed in your confirmation receipt: If airfare is a separate line item, then the travel agent is probably not legally obligated to get you to Orlando if that flight is cancelled or the airline ceases operations.
I hope this helps.