Shares in easyJet PLC (LON:EZJ) nosedived after the budget airline blamed 'Brexit', terrorism and strikes for lower revenue.
EasyJet also said it was difficult to predict fourth-quarter revenue due to uncertainty caused by the EU vote and the events in Turkey and Nice, which had hit consumer confidence.
Shares in the Luton-based airline fell 57p, or 5.1%, to 1070p as it said passenger numbers in the third quarter to the end of June rose 5.8% to 20.2 million.
But Total revenue per seat fell 8.3% at constant currency and by 7.7% on a reported basis to £54.54 per seat.
Total quarterly revenue dropped 2.6% to £1,196mln, as increased seat capacity was offset by the impact on yield of overall market capacity and cancellations due to "significant external events".
Commercial and operational performance during the quarter was impacted by the Brussels attack and Egyptair tragedy, significant disruption due to air traffic control strikes and congestion, runway closures at Gatwick airport and severe weather causing 1,221 cancellations.
EasyJet has said it may move its Luton headquarters out of the UK following the referendum vote. It said it was "committed" to the UK but said it had assembled a team to secure European flying rights.
It also has a plan to obtain an EU Airline Operator Certificate if the UK government negotiation does not achieve the desired outcome of a continuation of a liberalised and deregulated aviation market.
The airline has secured about 65% of expected bookings for the fourth quarter, with booked average revenue per seat for the quarter declining by around 7.5% at constant currency.
As a result of events in the last week, the revenue per seat trajectory in the fourth quarter remains uncertain.
Chief executive Carolyn McCall said: "The economic and operating environment has been difficult in the third quarter due to a number of factors including air traffic control strikes and other industrial action, runway closures at London Gatwick and severe weather.
"These factors combined with industry capacity growth in short haul continue to have an impact on industry yields at a peak time of year.
"More recently currency volatility as a result of the UK's referendum decision to leave the EU as well as the recent events in Turkey and Nice continue to impact consumer confidence.
"Despite this, easyJet carried more passengers and achieved higher load factors during the third quarter as easyJet's brand continued to resonate strongly across Europe. EasyJet is strongly controlling costs and driving continued improvement."