one way flights almost as much as return

[Hagabel]

Why are they not a lot cheaper one way?

[santhoshworld]

Why are they not a lot cheaper one way?

Mainly two reasons:
1. Because if a one way ticket was about 50% of the return price, than when the plane would be full for the return trip than you simply look for a different airline. If you sell relatively cheap return tickets and the plane is full (for one leg or both), than you don't go to another airline but check another date.
2. Because they rely partly on business travellers who will pay higher fares for one-ways because (unlike most tourists/travellers) they are not really sure when their return leg will be. So simply because they just get away with it.. Ever wondered why tickets might regularly be cheaper when there is a Saturday night involved? That's why.

So it simply means more reliability regarding having passengers on board of YOUR plane/airline.
You are also paying generally for more flexiblity regarding one-way tickets, but this is not always true.

Lowcost airlines have different policies though, with having the first cheap tickets being actually paid by people who book later and pay maybe more than regular airlines. In the end, the average price revenue might be the same.
That latter is what most people above ment and is easily explained by this.

credit goes to http://www.travellerspoint.com/forum.cfm?thread=61401

[victoria24]

any ideas of the cheapest time to fly to lhr return between march - september 2012?

[lizzyplop]

We are looking at the end of March 2012, and so far have found it cheaper to book two one way tickets, Air malaysia AKL-LHR and Singapore Airlines LHR-AKL.