New York → Barcelona

Transatlantic leisure demand is strongly seasonal: the summer travel season and the holiday periods at the end of the year pull the most passengers, and those are the weeks when fares hold firm and the cheapest classes vanish first. Trips built around fixed commitments — a wedding, a semester start, a conference — should be booked with a long lead time, because waiting rarely helps when everyone else wants the same dates.

If your calendar is open, treat the shoulder periods as your friend. Compare a spread of departure days here rather than a single date, and price the return leg on more than one day too — on long-haul itineraries, the combination that works out cheapest is often one you would not have thought to search. Staying an extra night or leaving a day earlier can move you into a different fare class entirely.

Start with breadth: comparing many airlines at once, including those that reach the route with a connection, gives you a far better picture than any single carrier's own booking page. Then read the fare rules carefully, because on long-haul tickets the differences that matter are baggage allowance, seat selection, whether changes are permitted and what they cost. A cheap fare with none of that included is not always the better buy.

Give the decision some time when your trip is still months out. Watching this route across several weeks teaches you what a normal price looks like, which is the only reliable way to recognise a good one. Pingsme is free to use, keeps every collected fare in one place and refreshes at least daily, so a final look before you book is always worth taking.