If you want a cheap flight from Inverness to Houston, you've got zero airlines to choose from.
Houston William P Hobby Airport is just one of the airports in Houston. If you're not set on a specific airport, try changing your search from Houston William P Hobby Airport to Houston to see a broader range of flights – they might be cheaper.
If you're planning on going to Houston during this time, you could take a look at other airport options. Or you could try to get a last-minute bargain.