The 737 Max aircraft is currently grounded after two crashes which killed 346 people. It was Boeing's fastest selling plane and earned the company billions of dollars in sales. Some of the money from those sales has been used to fund big pay-outs for company executives and shareholders. Since 2013, Boeing has paid $17bn (£13.74bn) in dividends to shareholders and has spent a further $43bn buying its own shares - a spending spree that has helped Boeing treble its share price in just five years. Chief executive Dennis Muilenburg has also been paid more than $70m.
Critics have accused Boeing of paying more attention to the stock market than the safety of its passengers. Economist William Lazonick said senior management were too focused on making money.
"If you supercharge the incentives of top executives and tell them that their job is to get the stock price up, they're not going to pay the kind of attention they need to pay to ensuring they produce a safe plane," he said.
Adam Dickson worked at Boeing for 30 years and led a team of engineers who worked on the 737 Max. He said they were under constant pressure to keep costs down.
"Certainly what I saw was a lack of sufficient resources to do the job in its entirety," he says. "The culture was very cost centred, incredibly pressurised. Engineers were given targets to get certain amount of cost out of the aeroplane."
Engineers were under pressure to downplay new features on the 737 Max. He said by classifying them as minor rather than major changes, Boeing would face less scrutiny from the US regulator, the Federal Aviation Administration.
"The goal was to show that those differences were so similar to the previous design that it would not require a major design classification in the certification process. There was a lot of interest and pressure on the certification and analysis engineers in particular, to look at any changes to the Max as minor changes."
He said that downplaying the changes reduced scrutiny in a way that could impact safety.
A single sensor was used to work out the angle the plane was flying at. On both the Indonesian and Ethiopian flights, that sensor stopped working properly. This resulted in MCAS forcing the aircraft downwards even though they were already on the correct course. The pilots struggled to regain control, because MCAS was designed to kick back in every few seconds. The Indonesian plane was forced down more than 20 times before it crashed.
Boeing said the pilots didn't completely follow the correct operating procedures when things went wrong. Boeing said it wasn't relying on the single sensor, because the pilots were there as back up. It said there was a way to override MCAS - a standard procedure that pilots should have known about from flying the old 737.
But 737 pilots like Chris Brady say it is wrong to blame the pilots.
"If you're going to design and certify an airliner with such a complicated, obscure failure mode as happened to that crew, it's no wonder that your average crew aren't able to deal with it," he said.