Be loyal. If your base airport is a hub for several carriers--such as those in Chicago or Denver--choose one and stick with it to accumulate points toward elite status. Even the lowest thresholds offer perks like early boarding and premium security lines.
Get an airline credit card. American, Delta and United have branded cards with perks that justify their fees ($95 to $150 annually) for anyone who travels more than twice per year. Perks may include discounts on in-flight purchases, free bag check and early boarding.
Buy a day pass for the lounge. Once restricted to club members, many lounges now sell day passes (about $50). You may not get unlimited martinis--many clubs charge for alcohol--but you will get soft drinks, snacks, Wi-Fi and a relatively serene waiting area.
Be a VIP. Global Entry status (globalentry.gov) allows access to expedited security lines with no removing of shoes, liquids or laptops. The application involves fingerprinting and an interview with U.S. Customs, but at $100 for five years, it's a bargain in pain relief.