The Boeing Company also provides eligible employees with an opportunity to enroll in a variety of benefit programs, generally including health insurance, flexible spending accounts, health savings accounts, retirement savings plans, life and disability insurance programs, and a number of programs that provide for both paid and unpaid time away from work. The designs range from commercially certified supplemental designs to military specific requirements and often involve military specific systems related to communications, surveillance, self-defense systems, aerial refueling, military cargo and airdrop, and weapons delivery.