After days of mounting pressure, the United States has grounded Boeing's 737 Max 8 and Max 9 aircraft.

President Trump announced the emergency grounding this afternoon.

"Any plane currently in the air will go to its destination and thereafter be grounded until further notice.  Pilots have been notified, airlines have been notified, airlines are agreeing with this," President Trump said. 

The U.S. following grounding of the aircraft by Europe, China, Indonesia, and early Wednesday, Canada.

Southwest, American and United Airlines were among the last carriers to fly the jet after one was involved in a second crash in five months. 

Concerns about the jet's safety came from Congress and passengers.

Some local officials have been proactive in trying to ban the Max 8, but Boeing maintains its confidence in its planes in a statement.

However, it recommends to the FAA the temporary suspension of the Max fleet.

The FAA said in a statement that the grounding will remain in effect pending further investigation, including the examination of those crucial black boxes.