The Part 135 Loophole: How Semi-Private Airlines Bypass Standard Airport Security

One hundred and twenty minutes. That is the standard buffer every major commercial airline demands you surrender before a domestic flight just to navigate the labyrinth of parking garages, bag drops, and security lines. But for a growing subset of travelers, that mandatory waiting period has shrunk to exactly 20 minutes.[1]

The experience of flying out of a Fixed Base Operator, or FBO, strips away the modern airport concourse entirely. There are no sprawling gate areas, no public address announcements, and no taking off your shoes. You pull up to a private terminal, hand your luggage to a valet, and walk directly onto the tarmac to board the aircraft.[3]

This is the operational model of the semi-private airline, a rapidly expanding middle market that bridges the gap between commercial economy and full private jet charter. "If the Wright brothers had seen what we've done to commercial aviation and all the barriers that we put between the individual who wants to get somewhere and getting on the airplane, they'd turn over in their graves," says Alex Wilcox, CEO of the semi-private carrier JSX.

The mechanism that makes this 20-minute arrival possible is not a secret VIP program, but a specific combination of federal aviation regulations. It relies entirely on the intersection of Department of Transportation (DOT) Part 380 and Federal Aviation Administration (FAA) Part 135.[2][4]

DOT Part 380 governs public charters. It allows a company—acting strictly as a charter broker—to sell individual seats on a flight directly to the general public.[4]

However, the company selling the ticket does not actually fly the plane. They contract a direct air carrier to operate the flight under FAA Part 135 rules, which govern commuter and on-demand operations.[2]

Part 135 is the critical regulatory lever. Traditional major airlines operate under Part 121, which mandates ultra-strict safety, rest cycle, and crew requirements designed for massive jetliners. Part 135 was originally drafted for smaller, on-demand air taxis.[2]

By capping the aircraft capacity at 30 seats—typically using modified Embraer ERJ 135 or 145 regional jets—these semi-private carriers legally qualify for the Part 135 framework while flying scheduled routes.[3]

The regulatory differences between the two frameworks are stark. Under Part 121, a first officer must have a minimum of 1,500 hours of flight time. Under Part 135, that minimum drops to just 250 hours.[2]

Furthermore, Part 135 pilots are not subject to the mandatory retirement age of 65 that governs Part 121 commercial pilots. This allows semi-private carriers to recruit both younger pilots building hours and highly experienced retired captains who still want to fly.[2]

But the most visible difference for the passenger is the security protocol. Because these flights operate out of private FBOs and fall under different security directives, they bypass the standard Transportation Security Administration (TSA) checkpoints found in commercial terminals.[1]

Passengers still undergo security screening—including TSA Secure Flight vetting, explosive trace detection swabs on luggage, and weapons checks—but the streamlined process takes seconds rather than hours.[3]

This regulatory arbitrage has infuriated major commercial airlines and pilot unions. Organizations representing traditional carriers argue that companies operating scheduled service should be held to the same Part 121 safety standards as traditional airlines, regardless of aircraft size.

The traditional carriers view the Part 135 model as an unfair competitive advantage, particularly during a nationwide pilot shortage, as it allows these upstarts to hire from a much larger pool of aviators.

In response to the mounting pressure, the FAA began scrutinizing the model in 2024. The agency has signaled intentions to evaluate whether these public charters should be moved into a new, stricter regulatory category to standardize oversight.

Proponents of the semi-private model argue that they voluntarily exceed Part 135 minimums by implementing advanced safety management systems, and that their operations provide vital connectivity to smaller regional airports that major airlines have abandoned.[3]

For now, the framework remains intact. Travelers willing to pay a premium over commercial economy can still legally bypass the terminal crowds and reclaim their time.[1]

The deciding factor will be the FAA's upcoming rulemaking process, which must determine whether a 30-seat jet flying a scheduled route is fundamentally a charter flight or a commercial airliner.[5]