There are some rudimentary ways. For example you set up ads based on search keywords, and try to base the ads and the page it takes you to based on the likely intent. For example, "visit france" is likely searched by someone who is thinking about learning more about it, but not purchasing or booking today. So I'd set up an ad and a web page dedicated to giving you interesting content about France, to make you more interested.

Then I can set up ads to hound you once you've visited that site, just in case you're still interested and remind you about that nice page I showed you. I can also look at my analytics to see what time and day most people book, and increase my spend on those times to play the odds that you too will make a booking at those times and days.

For a real example I'm proud of: recently a client of ours started promoting Beatles tours (visiting Liverpool and famous historical spots from their timeline). It coincided with the release of the new Beatles documentary, in exclusive cinemas for one night only. So, I set up ads to only appear to people searching for things about the film, or the Beatles, within 1 mile of each of those cinemas, for that one night. The ad said something like "Excited about the new film?" etc. My logic was people who were seeing the exclusive film would be the same kind of people who'd be interested in going on the tour, and while I didn't expect them to book that day, I got about 150 clicks, meaning there was interest. Maybe those people will book in the future. It was all about getting awareness of our tour up. Interesting project for me :)