LTA Reserch’s Pathfinder 1 airship turns heads skywards in San Francisco as flight test programme advances
November 24, 2025
US-based LTA Research has been flying its enormous Pathfinder 1 airship over the skies of San Francisco as the company expands its test programme and conducts longer-duration flights.
The latest series of test flights over the city forms just part of the aircraft’s preliminary steps towards a formal certification process.
It is hoped that these will culminate with the Federal Aviation Administration (FAA) clearing the way for full commercial operations of a derivative of the Pathfinder 1 in the future.
The LTA Research Pathfinder 1 airship
The airship is the brainchild of Alan Weston, who founded LTA Research in 2013 with funding from Sergey Brin, a co-founder of Google.
The founders are seeking to revive the concept of lighter-than-air technology by highlighting the potential use of airships for transporting cargo and people to remote locations.
To develop this concept further, the company has built its Pathfinder 1 rigid airship, which acts as a proof-of-concept vehicle for the company and its aspirations. In November 2023, the airship began its indoor tests, and in October 2024, it had its first untethered outdoor flight.
The Pathfinder 1 is said to be the largest aircraft in the world, with the construction of the prototype aircraft beginning in 2016. The airship measures 124m (406.5 ft) in length and is filled with helium to give it its lighter-than-air capabilities.
The craft is powered by 12 electric motors, which drive vectored thrust external propulsion fans controlled by the pilot via advanced fly-by-wire controls.
The use of these computerised controls, as well as stronger and more lightweight materials in the Pathfinder’s construction, is paving the way for a new generation of airships.
Equally, the use of helium over hydrogen (as used in airships in the past) makes the fuel source a much more stable proposition.
The addition of flame-retardant synthetic materials for the envelope (skin) of the airship adds to the safety characteristics of Pathfinder 1, supplemented by precise sensors to monitor the helium’s state throughout the aircraft’s operation.
Pathfinder 1’s flight test programme
The LTA team completed the first untethered flight of the Pathfinder 1 prototype (registered N125LT) on 24 October last year and has continued to develop the aircraft in the months since.
The first flight took off from Moffett Federal Airfield (NUQ) near the city of Mountain View, California, in the heart of Silicon Valley. The airfield is also the home to NASA’s AMES Research Facility.
Since then, the company has been expanding its horizons with test flights departing Moffett Field and heading north over the Bay Area and over downtown San Francisco, giving astounded bystanders unfettered views of the giant aircraft as it drifts lazily over the iconic Golden Gate Bridge, which separates the downtown area from the western suburbs such as Sausalito.
The first of these flights took place in May of this year.
The most recent of these flights took place on 18 November as the company sent N125LT once more over the city to test further systems, but also to draw attention to the LTA team’s efforts to demonstrate the capabilities of lighter-than-air technology to the public consciousness.
According to data obtained by Flightradar24, the airship took off from Moffett Federal Airfield shortly before 09:30 local time on 18 November and headed north. Having reached overhead the Golden Gate Bridge at 11:06, the aircraft then headed back down San Francisco Bay.
Passing between Oakland International Airport (OAK) and San Francisco International Airport (SFO), the aircraft then made several missed approaches back at Moffett Field, where the aircraft finally touched down at 13:05 local time.
Pathfinder 1 flying further and for longer
Although this was not the first public flight of the Pathfinder 1 over the Bay Area, the recent renewal by the FAA of the airship’s Special Airworthiness Certificate has allowed LTA Research to operate within an expanded flight envelope in the Bay Area and permitting test flights to reach further north. This flight was the result of that expansion authorisation.
What's being called the world's largest aircraft, the 124.5-meter-long Pathfinder 1, took flight this morning over San Francisco's Golden Gate Bridge. The massive airship, created by LTA Research, aims to kickstart an era of climate-friendly air travel that can potentially carry… pic.twitter.com/vFwrb2XPMd
— ABC7 News (@abc7newsbayarea) October 28, 2025
“Each phase of our flight test program incrementally builds our understanding of the proof-of-concept vehicle’s behaviour in different environments,” said an LTA Research statement.
”Flying over the Bay allows the team to gather new data on Pathfinder 1’s responsiveness, stability, and system performance during extended flight.”
“As we continue testing, each flight brings us closer to realising the potential of lighter-than-air technology to transform transportation for cargo and passengers,” the statement added.
The prospects for the airships of tomorrow
The future hopes of LTA see its airships having a wide range of applications from disaster aid and relief to outsized cargo transportation and low-impact sustainable passenger travel.
The firm states that airships such as those being developed by the company can deliver food and supplies to communities impacted by natural disasters when damage to roads, ports, or airports cuts off access.
Additionally, airships can transport high-value cargo, such as wind turbine blades, to remote areas by bypassing logistical barriers like narrow roads or bridges.
Lastly, by using 60% less fuel than traditional passenger planes, airships can offer quiet flight with low vibrations, particularly suitable for passenger flights over heritage sites and national parks.
“The future of airship technology makes possible the transport of people and cargo to destinations beyond the reach of roads, runways, and ports. Our vision is to develop the lighter-than-air technology that transforms air travel and rises to the world’s evolving needs,” concludes the company’s statement.
Featured image: LTA Research
