Easyjet's passenger numbers for last month climbed to 8.8m last month, including numbers it has taken from flying from Berlin's Tegel airport.
The number is an 14.2 per cent increase from September last year, when the airline carried 7.7m passengers.
Earlier this year the airline started operations at Tegel airport after taking over parts of Air Berlin, which collapsed last year.
Last week Easyjet said profit for the year was likely to come in between £570m and £580m, in the upper half of previous guidance.
"We now expect our headline profits for the year to be between £570m and £580m, at the top half of our guidance range," said Easyjet boss Johan Lundgren. "This has been achieved despite higher costs caused by disruption due to third party industrial action and severe weather.
"However, we have benefited from a number of one-off events in 2018, including the bankruptcies of Monarch and Air Berlin, as well as Ryanair cancellations."
On Tuesday Ryanair revealed it carried 13.1m passengers in September, an 11 per cent increase on the same time last year.