The Federal Aviation Administration (FAA) has granted permission to a further two drone operators to use the aircraft for business purposes. Along with agriculture, the development will see drones put to use in a real estate photography, a (legal) first for unmanned aircraft in the US.

The latest beneficiaries of FAA approval are the Arizona-based Tierra Antigua Realty and Advanced Aviation Solutions in Washington. In Tierra Antigua's case, a Phantom 2 Vision + quadcopter will be used in the production of real estate photography, already a popular application for drones in some parts of the world. Advanced Aviation Solutions will be using a fixed-wing eBee in agriculture to perform crop scouting and take photographic measurements from above.

These exemptions follow two recent rounds of permits granted by the FAA. The first of which, in September 2014, allowed six Hollywood companies to use drones in film production. The second concerned four US companies and involved a wider range of applications, including aerial surveying and construction site monitoring.

Slow progress in rewriting the laws surrounding commercial use has frustrated the industry, and business owners counting on drones to take their operations to the next level will be keeping a close eye on the FAA as it sifts through mountains of permit applications, granting exemptions on a case-by-case basis.

Quoted in a BBC report Jim Williams, manager of the FAA's integration office, argues that strict commercial regulations are required because "people who are being paid to do a job are more likely to take risks to accomplish that."

With regard to Tierra Antigua Realty and Advanced Aviation Solutions, the FAA gave the firms the green light after assessing their planned operating environments and outlining a number of requirements. The operations must have both a pilot and a second observer, the pilot must have an FAA Private Pilot certificate as a minimum and a current medical certificate, and the vehicle must only be flown within line of sight.