A travel blog can be profitable if done correctly. The first step is to find a niche. Once you have your niche, you need to research what is selling in that niche. You also need to create high quality content that is unique and interesting to your audience.
You also need to build an audience who will visit your blog regularly. Finally, you need to promote your blog and sell advertising space on it. If all of these steps are taken, a travel blog can be profitable.