A "relationtrip" is a fleeting romantic or passionate attachment that occurs specifically during a trip. This can technically be on vacation, but more commonly occurs during summer camp or missions trips. The aforementioned "relationtrips" last typically no more than 3 days after the end of said event. They can most often times be filed under "worst ideas ever".
A boy and a girl will create a "relationtrip" when they meet on the bus/plane on the way to summer camp or at camp itself. They will "date" (see; hold hands/maybe kiss) until the drive home and break up... if not sooner.