Oct 26 (Reuters) - Raytheon Technologies" (RTX.N) top boss warned on Tuesday the U.S. aerospace and defense firm will lose "several thousand" employees who refused to take COVID-19 vaccines, as it prepares to meet the Biden administrations" Jan. 1 deadline for immunization. "We will lose several thousand people," Raytheon Chief Executive Greg Hayes said in a CNBC interview on Tuesday, adding that staff hiring was underway. The company has a total of 125,000 U.S. employees. Raytheon, the maker of Tomahawk missiles, last month said it will require all U.S. employees to be fully vaccinated by mid-December, after the Biden administration mandated immunization for nearly all federal employees and contractors, to widen vaccination coverage in the country. read more Many federal contractors, such as Boeing Co (BA.N), 3M (MMM.N) and American Airlines (AAL.O), have announced vaccination mandates since. European planemaker Airbus (AIR.PA), which supplies helicopters to the U.S. Army, also joined the list on Tuesday. "We will require all employees and temporary workers of Airbus in the U.S. to be fully vaccinated against COVID-19 by Dec. 8," a company spokesperson said. Other companies such as Gillette maker Procter & Gamble Co (PG.N) also have mandates in place. To be sure, not every company is facing a pushback from its employees. United Food and Commercial Workers, the union which represents 26,000 workers at Tyson Foods Inc (TSN.N), said on Tuesday over 96% employees were now vaccinated. While some other large U.S. employers such as Walmart (WMT.N) were yet to issue broad requirements, the Labor Department"s standards will require them to introduce mandates. read more Separately, Raytheon"s Hayes said he expects Biden"s vaccine mandate to cause "some disruption" in the supply chain in a post-earnings conference call. General Electric, another federal contractor that has mandated vaccines, however, said it was too early to say if the decision would have an impact on the U.S. conglomerate"s operations. "We will have a better read as we get closer to the compliance date," GE Chief Executive Larry Culp told Reuters.