FILE PHOTO: A customer is reflected in a screen showing the schedule times of United at Newark International airport in New Jersey , November 15, 2012. REUTERS/Eduardo Munoz

(Reuters) - United Continental Holdings Inc said on Friday it would see a negative financial and operational impact on its business if Boeing Co’s 737 MAX jets remain grounded into the peak summer travel season.

The parent of the No.3 U.S. airline said it was operating 14 737 MAX aircraft that accounted for about 40 flights a day. (bit.ly/2TD4VLS)

United Airlines voluntarily ground all its 737 MAX 9 planes after two deadly crashes of another variant - the 737 MAX 8 - in recent months.

(This story corrects last paragraph to say company grounded 737 MAX 9 planes. It doesn’t own 737 MAX 8 aircraft)