Budget carrier Easyjet is in the process of recruiting more than 600 new customer service agents, an increase of more than 300%.
The airline said it has received an "unprecedented number of requests and enquiries" to its customer services team over the past few months.
The volcanic ash cancellations, as well as the heavy snow related delays in December and January, have led to a backlog of refund requests, complaints and enquiries.
Easyjet said it is falling "significantly below" its usual next day standard response time.
Customers are being urged not to chase their enquiries with further emails, as this will "increase the backlog that we need to deal with, slowing down replies overall".
www.easyjet.com