Labor must be tough to get and marketing in the regular sense probably won't work. You may think this cuts into profits but if any traveler asks an employee where to eat your restaurant name could come up first. Try happy hour for airport employees. Give discounted apps or drinks for after work employees. You have a big advantage as many employees like to get together after work for a drink and since there is no other sit down restaurants in your area your restaurant is the logical choice.
Happy employees talk and word of mouth is the best advertising for help.
Second, they need to make a fair wage and have decent benefits. Don't be cheap you'll get cheap help. Third, advertise correctly. Use bold print in your help wanted ad for the type of job you are hiring for. I noticed a 100 percent increase in the responses based on this type of change in my advertising.