May I please get a guide to solve this problem?

US Airways is one of the nation's leading commercial air carriers, with hubs Phoenix and Las Vegas. Here are some the costs incurred by US Airways (1. Airplane fuel, 2. Flight attendancs' salaries. 3. Baggage handler's salaries, 4. In-flight meals, 5. Pilots' salaries, 6. Airplane depreciation and 7. Advertising). A) For each cost, list the appropriate cost driver; B) Indicate whether the cost is likely to be fixed, variable, or mixed in relation to your cast driver