LONDON - British low-cost airline easyJet said its first-half performance would improve from last year as robust demand for flights helped it upgrade its forecast for revenue per seat.

EasyJet on Tuesday said it now expected first-half revenue per seat to increase by mid to high single digits, compared to a previous forecast for it to rise by low to mid single digits.

Reporting on the three months to Dec. 31, the airline also said its first-half headline pretax loss would narrow from last year, on strong demand for travel during its quieter winter period. It tends to make most of its profit in summer.

(Reporting by Sarah Young; editing by Kate Holton) ((sarah.young@thomsonreuters.com; +44 20 7542 1109; Reuters Messaging: sarah.young.thomsonreuters@reuters.net))