(Associated Press) – The CEO of United Airlines is frustrated about ongoing manufacturing problems at Boeing, and his airline will consider alternatives to buying a future, larger version of the Boeing 737 Max.

United Airlines CEO Scott Kirby said Tuesday on CNBC that Boeing needs “real action” to restore its previous reputation for quality.

United has dozens of Boeing 737 Max 9 jetliners that have been grounded for nearly three weeks after a panel blew out of an Alaska Airlines Max 9 in midflight.

Kirby is calling it the last straw for United.

So his airline will draw up plans for growing without a new, larger version of the Max that Boeing is developing.