After two Boeing 737 MAX tragedies we’ve come to learn a tremendous amount about the aircraft, how it was developed, and how it gained certification.

Engineering compromises were made to make the legacy Boeing 737 more efficient in a cost-effective way on an aggressive timeline. To compensate for aerodynamics issues created by moving the plane’s engines, Boeing created Maneuvering Characteristics Augmentation System (MCAS) software that could address an issue where the plane’s nose would pitch up, triggered by the aircraft’s angle of attack sensors.

• The system was being engaged based on data from a single angle of attack sensor. When that sensor generated a faulty reading, the software kicked in and forced the plane’s nose down ultimately with disastrous consequences.

• Many pilots of the aircraft type didn’t know about or understand the system, so didn’t understand what was happening when the system triggered and didn’t know how to override it.

• Some of the plane’s safety features were optional add-ons.

• These issues weren’t caught during certification, where it turns out that the plane didn’t even conform in some material ways to how Boeing indicated it was supposed to operate.

Planes with multiple angle of attack sensors, operated by pilots who understand the aircraft and all of its systems including handling MCAS, have operated without issue. But the 737 MAX’s design was more prone to disastrous failure when these circumstances weren’t present. So the aircraft manufacturer has updated the software so it won’t overwhelm pilots automatically when something goes wrong, and has worked on improved pilot training so aircraft operators are better equipped to handle things if they do.

I don’t have concerns flying the aircraft on a US airline. Doug Parker told the airline’s employees he’d be on the first flight. United’s CEO Oscar Munoz told media he’d take the first flight.

These moves will be meant to reassure the traveling public, who will at least initially be skittish. Southwest says they won’t charge passengers to change their flights to avoid the MAX once it goes back into service. Since Southwest already doesn’t have change fees, that presumably means no difference in fare.

A major concern is mixed messaging, the US FAA — which has taken lumps over certification of the aircraft and its response to the Lion Air and Ethiopian Airlines incidents — approving the plane for flight, while foreign regulators indicating they aren’t convinced. That would lead some to worry the agency was being pushed too hard by an American aircraft manufacturer and American airlines.

On Wednesday I wrote that the FAA would be trying to convince the world’s regulators to re-certify the Boeing 737 MAX. American Airlines CEO Doug Parker said he expects the plane to fly in ‘weeks, not months’ but that the FAA would want a critical mass of other world regulators to sign off on the plane as well as part of convincing the public that it’s safe to fly — however several countries would likely be recalcitrant for political reasons.

And no doubt politics plays into it. Some countries will want to stick it to Boeing as a proxy for trade disputes with the U.S. There are may be an opportunity for some countries to extract concessions from the U.S. in exchange for going along. And regulators can be inherently conservative, especially after two disasters, none want to be blamed or bet wrong and see another incident after they’ve signed off. Yet no one wants to operate the plane when there are mixed messages over its safety.

The FAA’s diplomacy has remained surprisingly diplomatic. It’s clear the FAA wants to see recertification soon, kicking off a process that will allow pilots to go through new training and airlines perform maintenance to bring aircraft back into their fleets.

While everyone publicly states that each country will make their own determinations, none have said they are officially unconvinced that the plane should fly or that the path the FAA and Boeing have laid out will be insufficient to see that happen. Instead regulators have remained non-committal on contentious issues like whether they’d require pilots to be simulator-trained on the MCAS system or whether home-based software training Boeing is pushing for will suffice.

The US government is ready to see the 737 MAX re-certified by the end of June — mere weeks from now, as Parker predicted. Whether or not that happens may depend on getting some other world agencies to go along. They won’t likely have unanimity, and won’t hold themselves to that standard. But I imagine they’ll hold off until they get Europe and Canada, though not China, to sign off with them.

Once that happens it will take time for airlines to go through steps to bring the plane back into their schedule, which makes cancellations through mid-August taken weeks ago by US carriers seem wise — and suggests that the process to bring the MAX back to the skies is proceeding as expected.