So here's a doozy.

Looking to fly back to the UK next Summer (mid-June) so started on Kayak looking for return flights from Salt Lake City to London.

Even this far off the costs were heinous to say the least - currently $1600 with American Airlines.

I used to pay as recently as a year ago about $900 (£600) for the trip in the other direction - London to SLC Return - When coming out for the ski season. And, this was booked with about 3 weeks to go, so relative to my new trip pretty much last minute.

So, I reversed the direction on Kayak for the same June dates next but London SLC return. $400 cheaper. Me no understand.

There will be negligible movement until 90 days before the flight. Then the prices are likely to become more variable, with occasional and significant fluctuations. I flew last summer (CLT->LHR end of May, returned in June) and found that in March the prices were mostly $1,425 +/-$75, but several times dropped into the the $1,200 range, or rose close to $1,600. I also noted a "sale" via Toronto for under $1,000, but blinked and missed it, however I was ready a few days later when another web site offered direct CLT-LHR flights for under $1,000. I snapped them up!

Tips:
(i) wait until less than 90 days to departure
(ii) patience, do not panic
(iii) try multiple sites (I was checking 4-5) and check them EVERY day, perhaps twice a day.
(iv)

Good luck!

I've always found www.momondo to be good...
There's skyscanner as well. If you can be slightly flexible with you're dates, that's a big bonus too.

Clear cookie/cache too...they like to know you're going back to their sites so don't always put the best prices up if you keep popping back.

Just booked our Christmas flights, CLT - LHR. Was constantly around the $1400 mark as said (and almost booked a $980 return via Toronto but was THREE flights on the way back taking 22 hours ) with the odd fluctuation and checking twice a day since July but paid $1100 through Skyscanner on Sunday. Website was actually 'getawayasap.com' and a Finnair flight (operated by US Airways).

Will be going back again in August and that flight is currently $1700

This. Without fail, Delta flights have gone up by $50 when I go back to recheck the price on a route I've already looked up. If you use IE, then use in private browsing when doing searches on airline sites.

Just read good things about Google Flights (speed, ease of use, flexibility in search parameters). Anyone used that to search?

plus in seems quite good when you do the search of finding cheaper fares on dates different to those selected, and highlighting them.

Another aspect to look at is airline loyalty schemes, i was pond hopping for 3 years prior to K1 and AOS (16 return trips) and settled for Delta airlines and signed up for their Skymiles programme, the variation in prices with search engines was so minimal when searching round that it worked out better. Ended up with extra luggage allowance, priority boarding, lounge access at Atlanta, priority check in, two upgrades to Business, all depends what you want when travelling.

I use it regularly. The matrix is useful for finding cheaper fares. Then book on the airline website (usually book premium economy on BA and then use a few thousand Avios points to upgrade to business).

Thanks folks. I'll reawaken my post as my original sign off was Me no understand and its still the case.

I've just gone on United's site and looked at SLC-London, 2 weeks from 1st June - $1900
The reverse direction - London-SLC, 2 weeks from 1st June - $890.

IN other words its less than 1/2 the price if the journey start and end destinations are simply reversed. Me very confused. Are we penalized some way in the US or what?

That's an easy one to explain! It is when US school holidays have just started in many areas, but it is still six or more weeks from the school holidays in the UK.

That said, I think others have commented previously that round trips starting in the US cost more than those starting in the UK.

Just checked prices in August (when both countries will be on school hols) and CLT-LHR-CLT is around $1900 whereas LHR-CLT-LHR is the usual $1450ish.

Bugger. That makes sense. Ba5t*rds.

The Airlines think Americans have more money than Brits. As long as they think they can get away with the higher prices they will charge them. Very annoying.