Buying airline tickets very early

I see none, as long as you can make all necessary payments now. Last year at this time we booked a long trip for April. Last month, seeing a great fare, we booked a London/Dublin trip for next April. As an aside to this, both these trips involved our wanting to stay at a couple places with limited availability (e.g. Boogaard's) that go quickly, and being able to plan that far out made it easy to get our lodgings.

We usually book our flights ~330 days out when they become available if we see a good fare we like. We have been in the habit of doing this since our vacation date was always set (we have recently retired though so we have more flexibility) and we wanted to see if there was the possibility of using FF miles. We have always booked way in advance and I don't see any problem with you booking 4 months out if your dates and location are decided.

This year we have a trip planned for mid-November but I purchased the tickets in January. I don't think the prices would have been too different later on in the year, but the real reason why I purchased so early was to reserve the exit row seats. We're flying on a Singapore Airlines Boeing 777-300ER and on this plane there are two economy sections, each with an exit row at the start of the section (for this reason there are no other rows in front of the exit row), however, the exit row of the second economy section is next to the bathroom (undesirable) while the exit row of the first economy section is not. Since the 777 seat config is 3+3+3, there really were only 6 highly desirable seats available. I was able to figure all this out with the help of SeatGuru. I'm not sure how quickly these premium seats go, but booking in January they were all open for the taking.

One thing to bear in mind if you book really early is that the airline may change the itinerary, the routing, drop a leg of the journey, etc. So just keep an eye on your booking to note any changes so that you have time to correct them. You don't want to get to the airport on the day of your flight either coming or going and have an unpleasant surprise.

Mary, good point. I forgot to add that in all my excitement of scoring these prized seats, I never bothered checking on the airlines website in all these months after booking, to see if there'd been any changes. When I finally did check this past weekend, I wasn't able to retrieve my booking/intinerary due to "change in flight", as the website said. After a long wait time with customer service, it turns out that the change was simply an arrival time of 10 minutes earlier than originally scheduled, but since this still constitutes a "change", my booking info was not accessible until I had spoke with someone to clear it up. The strange thing is, the error message on the website told me that due to this change, a representative would be contacting me to discuss. The thing is, I have no idea when this change took place and I'd never been contacted by anyone. It's just coincidental that I happened to check over the weekend that I came upon it. So yes, especially with long lead bookings, do check, perhaps monthly, that there's been no substantial change to your booking. The fine print will always tell you that the airlines do not guarantee any flight/seat and that anything is subject to change.

I, too, usually go ahead and book early. I like to assure myself of seating assignment that I most desire. Plus, none of the tickets I have bought have ever gone down in price, only up. I am already planning a trip next May and will book my flight no less than 180 days out.

http://finance.yahoo.com/news/no-easy-formula-best-time-165041924.html

Travelers dream of the perfect trick to find the cheapest airfare
every time, every trip.

There are theories, some of them backed up by real number-crunching —
shop on a Tuesday, 57 days before your flight. But using a tidy
formula to find the cheapest fare may be as futile as trying to time
the stock market.

"There isn't a golden rule anymore," says Patrick Scurry, chief data
scientist for Hopper, a travel-information firm that archives ticket
prices. "There are these 'average' rules, but they're not that useful
necessarily for a specific trip."

Airfares are set by supply and demand of seats. And 10 months out, airline analysts really cannot accurately project the traffic to set fares.
I start looking on MatrixITASoftware.com about 6 months out to get a feel of the upcoming airfares. And I'll monitor the current rates a couple of times per week--and watching the internet for signs of flight sales. I also go to ClarkHoward.com newsletters as they post rates daily. My intention is to usually purchase the flights around February for Spring flights.
Most of the time, we fly for substantially less than most people are paying. We leave next week for Copenhagen for $757 round trip, for example.

Good point about keeping on top of the changes, especially this far out. I am traveling (domestically) in about 2 weeks and I bought those tickets 4 months out. I've had 2 changes in that time, but nothing problematic. I am sure the earlier the more likely they will be changed.

I'm pretty happy with the fares I'm seeing so may pull the trigger. I'm not worried about the price dropping - it well might, but this is well under what I have budgeted so it may be worth it to lock in.

According to a 2015 study by expedia, prices for international flights start low (330 days in advance) and stay there until about 60 days out, when they start rising precipitously.

https://viewfinder.expedia.com/img/STOR-23513_White_paper.pdf

There is a very slight dip at 171 days out, but not worth waiting for if you are ready to buy earlier ( and want to choose your favored seats).

We purchased 2 tickets for $1353 per person on May 22nd for a British Airways flight to Spain on September 7th (routing is Vancouver/London/Barcelona outbound; Seville/Madrid/London/Vancouver inbound) . Since then the price of the flight has consistently gone down to as low as $929 per ticket which would have saved us $850 in total. We paid in Canadian dollars which has not done well against the US dollar, the Euro or the GBP in the last several months. If anything I would have expected the prices to rise based on currency fluctuation alone. This experience has left me shaking my head and wondering what is the right time to purchase tickets - early is definitely not always better.

We were emailed of a summer sale on Lufthansa with significantly lower prices, had to purchase in period in July, this was for departures August through October with return within 3 months. When looking at these, we also noticed that BA and US AIr did similar sales.