Can a minor purchase something online, such as a trip, in a parent's name without the parent's knowledge?

A minor can most likely purchase plane tickets and other items online in a parent's name and without their knowledge. For all intents and purposes, it was the parent that set up the purchase, changed their mind, and would like to back out. That will be their view of the matter, if it isn't already. This is because a profile to make the purchase was most likely set up in the parent's name; but, more importantly, is the fact that the child had access to the credit card to make the purchase. That's the clincher. Credit cards are to be guarded, like any other negotiable instrument - like cash, checks, bonds, stocks, etc.

A lot of adults try to use the excuse that it was "really" their child, a minor, who made the contract when, in fact, that is just a ruse to get out of an otherwise bad deal. So, these on-line companies have set up fairly sophisticated detections in that regard. However, it's not fool proof.

Suffice it to say, because your credit card number was available to your minor child, the odds are that this matter will eventually end up in collections, and then litigation. In the meantime, your credit will suffer.