Like other large US employers, Boeing spends millions of dollars each year on lobbying the administration and making campaign contributions. The company spent $US15 million ($20 million) lobbying in 2018, according to disclosure reports, more than household brands such as Amazon and Facebook.
Boeing ranked 11th in a Centre for Responsive Politics list of the nation's top spenders on lobbying in 2018.
The company contributed $US1 million to Trump's inaugural committee, Federal Election Commission records show. Boeing's employees, meanwhile, pumped about $US5 million into campaigns and political committees in last year's midterm election, according to a USA TODAY analysis of FEC data.
"This does not bode well for Americans who fly," Walter Shaub, senior adviser to the Washington-based Citizens for Responsibility and Ethics wrote in a post on Twitter. "Boeing donates $1 million to Trump's sketchy inaugural fund and the US breaks with other nations that have grounded the Boeing 737."
Large companies regularly contribute money to political candidates and spend heavily on lobbying. But what sets Boeing apart from most others is the care CEO Dennis Muilenburg has taken to cultivate a relationship with Trump, who owns one of the company's planes, a 757.
That relationship wasn't always so strong. During the 2016 campaign, Trump repeatedly slammed Boeing for the cost of its Air Force One design, suggesting it was "out of control". Candidate Trump criticised the company for setting up a plant in China to finish its 737s, saying it would take "a tremendous number of jobs" out of the country.
Shortly after the election, Muilenburg sought to smooth things over with the president during a visit to Trump's Florida estate, Mar-a-Lago. A month later, and days before Trump became president, Muilenburg appeared at Trump Tower, praising Trump's "engagement".
When it came time for Trump to make his first trip out of Washington in early 2017 he went to a Boeing plant in South Carolina to tout US economic growth. The company was later awarded a contract to build two Air Force One planes for $US3.9 billion.
"We've got a whole wave of policy issues, topics we're working on," Muilenburg told analysts on a call last year, "but we have a voice at the table, which is encouraging."
A member of Trump's cabinet, acting Defence Secretary Patrick Shanahan, spent more than three decades with Boeing as an executive before joining the administration in 2017.
Trump has continued to praise the company even as he announced the grounding.
"It's a great, great company with a track record that is so phenomenal," Trump said at the White House on Wednesday. "And they want this solved; they want it solved quickly."
Still, the company has had a mixed track record meeting its policy ambitions in Washington. Muilenburg personally spoke with Trump to lobby for the safety of the 737 Max 8. And the FAA initially stood by the plane as Britain, France and Germany joined a growing list of countries suspended its use in their airspace.
US regulators relented on Wednesday, citing new information from the crash site and satellite data that the agency said suggested similarities between the Ethiopian Airlines crash on Sunday that killed 157 people and the crash in October of a Lion Air Flight off the coast of Indonesia that killed 189 passengers and crew.
"Pilots are no longer needed, but rather computer scientists from MIT," Trump posted on Twitter days after the crash, a missive that preceded Muilenburg's call to the White House. "I see it all the time in many products. Always seeking to go one unnecessary step further, when often old and simpler is far better."
Experts said Boeing has long been a major player in Washington's influence game, but noted there was no evidence that effort had anything to do with the FAA's delay in grounding the latest 737 model. The federal government spent $US23 billion with Boeing in 2017, a US General Services Administration report on federal contracting shows.
"They're really good at capturing defence contracts," said Richard Aboulafia, vice-president for analysis at Teal Group and an aviation consultant. "But there's absolutely no evidence that there's anything untoward with the FAA's decision here."
A Boeing spokesman did not respond to a request for comment.
Like many other agencies in the Trump administration, the Federal Aviation Administration isn't working at full capacity. Daniel Elwell, a former Air Force lieutenant general and American Airlines pilot, has been serving as the agency's acting administrator for more than year.
Trump floated the idea of nominating his personal pilot for the top FAA job last year, but backed down following resistance from lawmakers.
The National Transportation Safety Board, by contrast, is a five-member board that investigates crashes and makes non-binding recommendations on how to avoid future mishaps. Trump appointed two of its five members and elevated a third - originally a Bush appointee - to chairman. The board has one vacancy.
The NTSB is not investigating either the Ethiopian crash or the Lion Air crash. Foreign countries must request NTSB or similar European agencies to investigate.
Mike Slack, a pilot and lawyer who has represented passengers and family members in crash cases, said Trump had little choice but to ground the Max 8 and Max 9 planes. Allowing the aircraft to fly would have gambled jobs - and American lives - and raised even more questions for the administration and Boeing.
"Is this about protecting Boeing competitively against Airbus, its primary competitor? And why would Boeing's CEO be calling the president of the United States?" said Slack, a former NASA engineer. "That's not good form when the background story is already that the FAA is not acting."