[05/13/2016 @ 1:13 PM] KLM now offering AMS nonstop for $615. Also, most prices have dropped a little bit since this was originally posted.
[05/13/2016 @ 5:17 PM] AA has matched many of these destinations. Noteworthy, London is nonstop for $695.
[05/17/2016 @ 2:50 PM] Fare gone. Removing from deal list.
Delta and SkyTeam partners have round-trip flights from Houston (IAH / HOU) to multiple cities in Europe for $489-$770. Flights departing mid-September to at least March 2017. Carrier will depend on dates / destination selected. Most flights have either one or two connections. Holiday blackouts apply somewhat (see note). 7-day minimum stay required.
Note: Most of the flight prices in September and October are going to be about +$100 more than the lowest price listed below. If you want the cheapest dates to fly on, you’ll want to pick flight dates after October.
Note: It’s possible to book the Wednesday before and after New Years for most of these destinations.
