At Capitol Hill on Thursday, the National Air Traffic Controllers Association (Natca) was joined by NBAA, ALPA, GAMA, NATA, HAI and Professional Aviation Safety Specialists (Pass) in a rally against the government shutdown. Heavy rain, as well as Capitol security, dampened attendance to about 150 people, who were supplied by Natca with matching signage and shirts.

Besides coalescing for the rally, the groups also sent a joint letter to Department of Transportation Secretary Anthony Foxx seeking to end the furlough of thousands of safety inspectors, an action they said has “eliminated critical layers of redundancy and safety.” They also asked Foxx to restore the aircraft registry in Oklahoma City to clear its backlog of applications, which are growing by 10,000 each month.

During the rally, NBAA president and CEO Ed Bolen said that the registry should qualify as an “essential service,” exempt from the shutdown, since it supplies security information to the TSA that is “vital to protect human life and property.” With the shutdown now in its 15th day, GAMA said that up to 150 aircraft deliveries worth $1.9 billion have been stalled to date. Fourth-quarter deliveries–a third of annual volume–could plummet as a result, GAMA warned.