Early history

The first airplane to land at what is now Trenton–Mercer Airport touched down in 1907, in what was then Alfred Reeder's farm field, just off of Bear Tavern Road in Ewing. Twenty-two years later, in 1929, Skillman Airport opened to the public.

During World War II, the nearby General Motors Inland Fisher Guide Plant ceased producing civilian vehicles and began making Grumman TBF Avenger carrier-based torpedo bombers for the United States Navy. Skillman Airport expanded at this time to accommodate test flights of this aircraft, and after the airport returned to county control following the end of the war, it was renamed Mercer County Airport. After the war, the navy reestablished a presence with the construction of Naval Air Warfare Center Trenton adjacent to the airport, which remained open until 1997.

Commercial service era

Allegheny McDonnell Douglas DC-9-30s nonstop to Chicago O'Hare Airport in 1977 were probably Trenton's first jet flights. According to the Official Airline Guide (OAG), the only airline serving Trenton in 1976 was Allegheny Commuter operating small Nord 262 commuter turboprops with nonstops from Newark and Philadelphia as well as direct one stop flights from Washington National Airport with all service operated on behalf of Allegheny on a code sharing basis.

The airport's air traffic control operations, based in the control tower, operated between 6AM and midnight during the 1980s and early 1990s. Since January 1994, tower operations have been shortened to 6AM and 10PM.

United flew mainline jet service with Boeing 727-200s and Boeing 737-200s to Trenton direct from Chicago O'Hare Airport in 1984–86. According to the Official Airline Guide (OAG), by late 1989 USAir Express was the only airline serving Trenton with flights operated with small British Aerospace BAe Jetstream 31 commuter turboprop airliners nonstop from both Baltimore and Washington National Airport, flown via a code sharing agreement with USAir.

In 1994, as a cost-cutting measure, the Mercer County Airport Police and Fire Department was disbanded and replaced by the Mercer County Sheriff's Office (police) and ProTec Fire Services (Aircraft Fire Rescue). The following year, in 1995, the airport's name was changed to Trenton–Mercer Airport in an effort to identify it with the city of Trenton – the capital of New Jersey and county seat of Mercer County.

During the mid-to-late 1990s, Eastwind Airlines operated a hub out of Trenton to Florida and North Carolina as well as airports in Massachusetts, New York and Pennsylvania. The airline also flew from Philadelphia for a short time. This was one of the few instances where Trenton–Mercer saw scheduled jet service from its short runways with Boeing 737-200 and 737-700 aircraft although other airlines operated jet service, as well.

From 1998 until 2003, Shuttle America operated a scheduled business commuter service to airports in Connecticut, Massachusetts, New York, Delaware, and North Carolina. The airline flew 50 seat de Havilland Canada Dash 8-311 turboprops and had all its aircraft stocked with in-flight service items when stopping in Trenton. The airline ceased operations at TTN after a codeshare service with US Airways drew customers to nearby Philadelphia from Trenton.

Also occurring in 1998 was the completion of the airport's NWS/FAA automated surface observing system (ASOS), replacing the human weather observers that had previously reported weather conditions; the facility became operational on March 11 of that year.

Beginning in May 2000, Boston-Maine Airways operated the Pan Am Clipper Connection between Trenton–Mercer Airport and Hanscom Field in Bedford, Massachusetts. The flight operated until 2008, was terminated when Boston-Maine Airways ceased operating on February 28 of that year.

In 2006 and 2007, Comair flew to Atlanta and Boston from Trenton as Delta Connection, using Canadair CRJ-200 regional jet aircraft. After a few months, Big Sky Airlines took over the Boston service with Beechcraft 1900 commuter turboprops. The service ended in early January 2008.

On April 4, 2011, Streamline Airlines briefly re-commenced the former Pan-Am Clipper Connection route between Bedford–Hanscom and Trenton, using an Embraer EMB-120 Brasilia turboprop. The carrier was consistently losing money and shut down on September 14, 2012, citing a poor economic climate and unprofitable operations.

In 2012, Frontier Airlines began service at Trenton with flights between it and Florida, utilizing the Airbus A320 family of aircraft. By early 2013, the airline began expanding service and established a base at Trenton.

On November 8, 2013, TTN opened a renovated terminal – including a new modular trailer baggage claim outside the terminal, restrooms in the gate area (there were previously no restrooms past security), and additional passenger seating and a new gate in the area formerly occupied by the original baggage claim.

In August 2014, the airport was awarded $2.2 million to rehabilitate three taxiways.