Originally Posted by
ouwejan
When checking KLM flights, I noticed that when there is a time frame of more than 3 months between the outbound and inbound flight, prices suddenly increase. What's the reason for this?
No real reason, simply because they can....
And it's rather useless trying to figure out the why airlines price the way they do, simply use a decent search engine like Kayak.com or the ITA matrix to find the cheapest ticket. Being flexible with dates and routes can save you money. And do not only search from AMS-IAD but look at BRU/DUS/NYC as well.