Yes, they will be fine. Film is sensitive to heat, but for periods as short as a few hours, there will be no noticeable deterioration. People sometimes fret over this issue as if film were a dairy product; it's not that sensitive.

But, don't expect fantastic results from disposable cameras in any case. They are fun, but they use cheap, slow plastic lenses, and the film inside is not as sensitive as a digital sensor. Use them in good light (outdoors), and you should get some pleasing results.

One more thing - do not put these cameras in your checked luggage. Keep them in your hand luggage. Checked luggage is scanned with X-rays that are strong enough to damage film inside. Hand luggage also goes through X-ray scanners, but at a lower level.