Although the two grounded flights involved air planes of similar models, airline officials said they ‘do not want to speculate on whether [the two incidents] are linked’ until investigations have been completed.
One passenger on the Miami-bound flight told Daily Mail Online she saw people ‘pass out’ from the mystery illness before the plane landed.
‘We are currently still in Brasilia where we made an emergency landing because crew members and passengers passed out and became unwell,’ the woman wrote in an email.
‘It sounds exactly like what happened on the other flight with us not being allowed off the plane for two hours.
‘As you can imagine frustrating chaos followed and most people are stuck here for 48 hours. One of the crew said something about oven cleaner reacting badly.’
Another passenger, Xime Etchart, wrote on Twitter early Friday morning: ‘Emergency landing in Brasilia from Rio to Miami. We’re all still waiting for an update on when we are flying back…’
In a second tweet, Etchart wrote she’d been stuck in Brasilia for six hours with ‘no food, no room, no help at all.’
The Miami-bound Boeing 777, which carried 203 passengers and 14 crew members, was of a similar model to the one that was forced to divert back to London Heathrow following a ‘medical emergency’ on Wednesday.
The captain on the flight from London to Los Angeles made the decision to turn around after increasing numbers of people on-board became ill.