(Reuters) - Defense contractor Lockheed Martin Corp said on Friday it plans to increase the workforce at its approximately 300-person Milwaukee facility by more than 15% this year.

The announcement in a company tweet came after President Donald Trump gave a 30-minute speech on trade at the plant, which is run by Derco, a unit of the F-35 fighter jet maker.

Lockheed Martin Chief Executive Marillyn Hewson said the company planned to hire 18,000 people overall this year and gave much of the credit for the expansion to Trump, as she made remarks introducing the president.

"The main reason for that, Mr. President, is because of the pro-growth policies that you have put in place on tax reform and regulatory reform," she said.

In his remarks, Trump thanked Hewson for her decision to keep open a Sikorsky helicopter plant in Pennsylvania that had been slated for closure. Trump called Hewson's decision "a beautiful favor" and said, "They’re really happy in Pennsylvania right now."

Pennsylvania and Wisconsin are expected to be critical to Trump's re-election effort next year.

Hewson, in an announcement on Wednesday, said she reversed course on Sikorsky "at the request of President Trump."

This week was not the first time that Lockheed has responded to pressure from Trump. Shortly before Trump took office in January 2017, Hewson said Lockheed was close to a deal to significantly lower the cost of the F-35, after Trump the prior month had said he was asking rival aerospace company Boeing Co if it could offer a cheaper alternative to the fighter aircraft. [D-REUTERSNEWS-T004/I8855d940d9be11e6a1e9955aa2f1af39]

Trump has campaigned on rebuilding the manufacturing sector to create high-paying American manufacturing jobs, partly by pushing other countries for more favorable terms on trade.

Derco, which makes aircraft spare parts, also provides logistics and technical support for fixed-wing planes.

(Reporting by Sanjana Shivdas in Bengaluru and Eric Beech in Washington; Editing by Leslie Adler)