Rainmaker Technology’s proposal to use small drones equipped with cloud-seeding flares is facing opposition from the airline pilots union, which has asked the Federal Aviation Administration to reject the company’s application unless more rigorous safety protocols are met.
The outcome of the FAA’s review will reveal the agency’s stance on using drones for weather modification in the future. Rainmaker’s future plans for drone deployment depend on this decision.
The Air Line Pilots Association (ALPA) has informed the FAA that Rainmaker’s request “does not provide an equivalent measure of safety” and creates “a significant safety hazard.”
On the other hand, Rainmaker CEO Augustus Doricko stated in an email that the union’s criticisms are solely based on the public filing, not on confidential documents submitted to the FAA that detail the company’s safety measures and risk assessments.
Rainmaker is requesting a waiver from regulations that prevent small drones from transporting dangerous materials. The company submitted this request in July, but the FAA has yet to make a decision and has instead asked for more details concerning operational and safety procedures.
In its application, Rainmaker outlined plans to use two types of flares—one that burns in place and another that can be ejected—on its Elijah quadcopter to release particles that trigger rainfall. The Elijah drone can reach up to 15,000 feet above sea level, within the controlled airspace frequented by commercial jets. Drones must receive Air Traffic Control approval to operate in this zone.
Rainmaker’s application indicates that operations will be limited to Class G (uncontrolled) airspace unless otherwise permitted. ALPA points out that the application lacks specifics on the locations and altitudes of these flights. Doricko, however, explained that the confidential documents provided to the FAA specify that flights will not exceed 15,000 feet MSL and will only be conducted in airspace deemed safe by aviation authorities, “eliminating any logical worry about high-altitude operations or airspace management.” ALPA did not respond to TechCrunch’s requests for feedback.
The union also challenges the use of flares, expressing worries about debris and potential fire hazards. ALPA further notes that the application does not feature trajectory predictions for the ejected flare casings or any study on the environmental consequences of the chemicals used.
“On the topic of flares, independent organizations such as the EPA and numerous state natural resources departments have researched both the spread and environmental safety of cloud-seeding materials for more than 70 years and have never found any negative consequences,” Doricko said.
Sam Kim, who oversees aviation regulatory matters for Rainmaker, mentioned that the company values its relationship with the pilots’ union and aims to further strengthen this partnership, but argued that the union’s objection “shows a misunderstanding of the reasons behind Rainmaker’s application for the exemption.”
Kim also noted, “Our deployment of flares on unmanned aircraft is strictly for research within a supervised flight area, and does not reflect our broader ongoing operations.”
Doricko explained that a standard Rainmaker mission releases between 50 and 100 grams of silver iodide, and even less during a flare-based flight, whereas a single hour of commercial airline operation emits multiple kilograms of volatile organic compounds, sulfur oxides, and soot—far surpassing the emissions from Rainmaker’s activities.
“Rainmaker strives to conduct the most responsible and advanced atmospheric studies possible, which is why we are evaluating flares against our unique aerosol dispersion system designed to exclusively emit silver iodide and replace flares. ALPA’s stance on this issue highlights their incomplete grasp of our Concept of Operations, which includes detailed risk management measures outlined in confidential submissions currently under FAA review,” Doricko said.
Doricko also addressed airspace safety, saying, “Regarding ALPA’s points about coordination and airspace management, our flight procedures involve radio broadcasts, direct collaboration with local air traffic control, certified pilots, and a collision avoidance system that uses both electronic and human spotters.”
Rainmaker added that its drone flights will take place above rural regions and over properties owned by private individuals “with whom Rainmaker has established strong partnerships.”
Traditional cloud-seeding is already performed, mainly across the western United States, using piloted aircraft in cooperation with state agencies. Ski resorts contract these flights to maintain snow coverage, and water management districts utilize them to build up snow reserves in winter for use during the spring thaw.
Cloud seeding as a practice has been around since the 1950s. By dispersing tiny particles into specific clouds, scientists discovered they could prompt rainfall. Silver iodide is generally used for these particles because its structure resembles that of ice crystals.
When a silver iodide particle interacts with super-cooled water droplets, it causes them to freeze instantly since the droplets’ temperature is already below freezing. If conditions are favorable, these ice crystals can rapidly increase in size, often outpacing the growth of liquid droplets. Furthermore, the quick formation helps the crystals persist longer than liquid water droplets, which might evaporate before falling as rain.
Rainmaker’s unique approach—using drones instead of crewed flights—may offer greater safety over time. The company emphasizes that their drone missions are tightly regulated, led by remote pilots and trained teams, and are conducted above sparsely populated areas with additional safety precautions in place.
The next steps depend on whether the FAA finds these safety measures adequate. Whatever the outcome, the FAA’s ruling will likely influence how innovative cloud-seeding techniques are treated in the future.
9/13/2025: This article has been revised to add remarks from Augustus Doricko, founder and CEO of Rainmaker, and Sam Kim, the company’s aviation regulatory manager.
