“The cheapest flights are always booked online” is a theme I push on the main site. 90% of the time this is true. Maybe 10% of the time it couldn’t be further from the truth. It all depends on the types of flights you’re looking for. The real discounts aren’t found online.
A simple return flight to, for example, Buenos Aires, travelling in the off peak season and booking well in advance almost always is cheapest booked online with one of the online flights specialists (eg. Travelocity). A return flight on the same route travelling the weekend before Christmas, returning the weekend after New Year (or similar popular dates), is a different matter. These dates will always be expensive, but by getting on the phone to a flights specialist, you can save a lot. When I worked as a flights consultant, I booked long-haul economy class flights for people that were up to £300 ($600) less than anything they could have found online. How?
Some flights specialists use tricks to book flights for less than they should be. The tricks invariably work best when availability is limited (flights are busy). Computer reservation systems used by flights agents (eg. Amadeus, Sabre) allow a high degree of manipulation by a savvy flights consultant. Iberia, Air France, KLM, Lufthansa, American Airlines, Delta Airlines ,Varig and Alitalia are all open to manipulation in the hands of a savvy flights consultant. In a nutshell, the airline will release seats at different prices from different destinations - you want a flight from London to Buenos Aires via Frankfurt? I’d book it from Tokyo via Frankfurt to Buenos Aires, cancel the Tokyo to to Frankfurt leg (in a very complicated manner), and add a London to Frankfurt flight, and it costs £200 less. It’s complicated, but some flights specialists can do these tricks - online flights reservation systems can’t. If flights on your travel dates seem expensive - get on the phone, and hope you get though to a savvy consultant.
There’s other examples of when booking flights on the phone can be much cheaper than booking them online. The main case is in the use of airpasses - eg. flights within a country, or within a continent. Here’s an example: I need a one way flight from Sao Paulo to Panama City in February (I actually do need this flight). A Hahn airpass (All America Airpass) costs a bargain $259 + tax. The only way I can book this is by speaking to a South America flights specialist. Prices online are more than double. Multi-stop airpasses are similar in nature - you can’t book them online. Four flights within Brazil booked as a Tam Airpass over the phone is likely to be well over 50% less than if they were booked online. In a similar fashion, Lan also has a great value airpass for flights within Chile, Argentina, Peru and Ecuador - again, you can’t book it online, so get on the phone.