LONDON, Oct 12 (Reuters) - British airline easyJet said on Thursday it had reached a proposed deal with Airbus to expand its fleet by up to 257 additional aircraft, plotting its growth beyond 2028, with bigger and more fuel efficient planes.

EasyJet said the proposed purchase, which is subject to shareholder approval, would add 157 aircraft plus the rights to 100 more, with the majority being A321neo planes for delivery between 2029 and 2034.

"This will enable easyJet's fleet modernisation and growth to continue beyond 2028 while providing substantial benefits including cost efficiencies and sustainability improvements," chief executive Johan Lundgren said in a statement.

The group also said it planned to convert an order for 35 A320neo planes into the bigger A321neo jets.

For the 12 months to the end of September, easyJet said it expected to post pretax profit of between 440 million pounds ($542 million) and 460 million pounds, broadly in line with an LSEG forecast of 454 million pounds.

EasyJet also said it would reinstate its dividend later this year after it stopped payouts during the pandemic.

($1 = 0.8120 pounds) (Reporting by Sarah Young, Editing by Paul Sandle)