You can book flights for someone else on OneTwoTrip.com and pay for such flights with your card. However, at check-in the person(s) you booked the flight(s) for may be requested to present the cardholder's express consent approving the purchase. Such consent can be written in a free form and should contain a photocopy of the card and cardholder's signature.
If you provided your contact details during the booking process, please make sure the passengers for whom you booked the flight(s) are aware of the selected fare rules as well as of User Agreement.