Amsterdam → Barcelona

Because this route is dominated by leisure travel, demand rises and falls with holiday periods rather than with the business week. School breaks, long public-holiday weekends and the height of the summer travel season are when the cheapest fare classes disappear soonest. If you are travelling as a group, that pressure is amplified: several seats at the same low price on the same flight are much harder to find than one.

Where your dates can move, use that freedom deliberately. Compare consecutive departure days on this page instead of committing to the date you first had in mind, and check the weeks either side of the busiest period. Mid-week departures often price differently from the Friday-out, Sunday-back pattern most short trips default to, and simply reversing which nights you stay can change the total.

On a route with several competing airlines, the useful comparison is never one carrier against your memory of what flights usually cost — it is all of them, side by side, on the same dates. That is the fastest way to see the real floor of the market. Once you have candidates, check the fare rules: hand baggage allowances, checked bags and seat selection differ enough between airlines that the ranking by total price can be quite different from the ranking by advertised price.

If your trip is still weeks away, resist booking on the first search. Follow the route for a few days, get a feel for how far fares swing, and book when a price sits at the low end of that range. Pingsme costs nothing to use, updates at least daily and keeps every collected fare in one place, so re-checking before you pay is the cheapest step in the whole process.