When my daughter went to Israel with the intention of making aliyah, I booked her a one-way through Manchester. The Manchester to Tel Aviv leg was on Jet2. I got a call at 3 AM NY time from Manchester. They wouldn't let her on the plane without evidence of a return ticket. I went online and booked a cancelable one-way return flight on El Al and faxed the receipt to them. The next day, I cancelled it.