Student or Learner
suppose i want to buy airplane tickets.
the return ticket must have a date that is the furthest possible one.
if the air company allows me to buy the return ticket for 1 year from now, it's great! if they allow me to buy it for 2 years from now, better!
how do i say it in a simple and understandable way?
You can't buy an air-ticket for a period longer than a year, so there is no way you could say that.
You could ask for an open-ended ticket which will be valid for one year from date of purchase.