ROCKFORD, Ill. (WTVO) — An environmental advocacy group has sued the FAA for allowing Rockford’s airport to continue expanding on the Bell Bowl Prairie.

The Natural Land Institute (NLI) and supporters rallied at the Winnebago County Courthouse Wednesday evening to raise awareness.

The FAA ruled earlier this week that RFD will retain more than six acres of the prairie land. A federal court denied a motion by NLI to halt work on the project on Wednesday.

The group had hoped to delay work until after March 15, which would have forced the airport to wait until October to complete the project to avoid harming the endangered rusty patch bumble bee.

NLI claimed that work on the cargo expansion project could restart as soon as Thursday.

“We’ve given them opportunities for redesign, we’ve come up with ways to fund the redesign, but it’s falling on deaf ears. It’s falling on bad ego, need to be right,” said Kerry Leigh, executive director of the Natural Land Institute. “It’s so disheartening.”

Airport administrators said that the $50 million project will create hundreds of jobs for the region.