Istanbul → to Barcelona

Yes — the seasonal median for this route is around $180 round-trip. At $143 you're 21% below that, which we rate good for this route.

Across 12 months of cached-fare history, Dec comes out cheapest on this route. The best months to actually be in Barcelona are May–Jun · Sep–Oct — when those overlap, that's your window.

We do not publish a number for this, because we cannot measure it yet. Answering it honestly means watching the same departure date on this route over many weeks as it approaches, and that archive is still filling up — so any "book N days ahead" figure here would be borrowed from somewhere else rather than measured. What we can measure is which month is cheap: across 12 months of cached fares, Dec comes out lowest on this route. Our guide Why flight prices change covers what does move a fare.

Yes — the current board includes nonstop fares (Vueling). The outbound leg runs around 3.5 hours.

No — these are cached fares found on real searches (this one on 17 October). Airlines reprice constantly, so the booking search re-checks the live price before you pay. Fresher finds are far more likely to still be available.