The Trump administration said Thursday that just 776 air traffic controllers and technicians who worked during the longest government shutdown in history will be awarded $10,000 bonuses for their “perfect attendance.”

The bonuses will be doled out no later than Dec. 9, according to a Federal Aviation Administration announcement.

“These patriotic men and women never missed a beat and kept the flying public safe throughout the shutdown,” Transportation Secretary Sean Duffy said in a statement.

The National Air Traffic Controller Association (NATCA), a labor union for more than 20,000 air industry workers, told Fortune it was informed Thursday afternoon of Duffy’s decision to issue the cash awards to 311 of the workers it represents.

“Although we agree that the work performed by these aviation safety professionals during the shutdown deserves recognition, praise, and our collective gratitude, we are concerned that thousands of air traffic controllers who consistently reported for duty during the shutdown, ensuring the safe transport of passengers and cargo across the nation, while working without pay and uncertain of when they would receive compensation, were excluded from this recognition,” NATCA said in a statement.