An average travel affiliate will make next to nothing selling affair, a little more selling car rentals, and can potentially make a lot selling hotel rooms. The average commission per sale is much lower than what you would see promoting online gambling or some other lucrative industries, but if you do sufficient volume, you can make a very nice living indeed.
The thing about travel is that it’s such a deep and broad market with so many keywords to target.
There are only so many keyword phrases related to “online gambling” “online casino” “online blackjack” etc.
Travel has a boggling number of niches that you can target because there are so many destinations. Compared to “online gambling” phrases, there is minimal competition for some niche keyword phrases. A search for “hotels near the superdome in new orleans” only has 12,000 pages competing for it. New Orleans has several potential points of interest to me near, and so does every other major destination, so you can see how you could generate some fairly high ranking pages targeted at niches that could make money in travel. Especially if you don’t rely on PPC.