My ALO mainly asked me questions off of my resume. That being said, know every detail of your resume by heart. Additionally, I recommend asking yourself questions such as:
1. Why do you want to attend the service academy of your choice?
2. What makes you qualified to attend a service academy?
3. What do you aspire to pursue in the Unites States Air Force?
You can search more of the frequently asked questions online.
The interview with your ALO is extremely important to your application. It's one of the few ways the academy can truly see who you are as a person. That being said, be confident and relaxed. You got this.
Best of luck!