Here’s a concise, practical list of the best budget (low‑cost / ultra‑low‑cost) airlines worldwide — grouped by region with a short note on why each is recommended and a few quick tips for using budget carriers.

Top global picks (from recent passenger/industry rankings)

• AirAsia — consistently rated the world’s best low‑cost airline (strong Asia network, frequent sales). (skytraxratings.com, worldairlineawards.com)
• Scoot — one of the top long‑haul low‑cost carriers (good value on medium/long haul within Asia and to Australia). (skytraxratings.com)
• IndiGo — India’s dominant low‑cost carrier (huge domestic network, punctuality). (skytraxratings.com)

Best by region (short list and why)

• Europe: Ryanair, easyJet, Wizz Air, Vueling, Volotea, Jet2 — largest networks and frequent ultra‑low fares across Europe. (Watch add‑on fees for bags/seats.) (airadvisor.com, wowfare.com)
• North America (U.S.): Southwest (value/hybrid model — no change fees, 2 free checked bags), Spirit, Frontier, Allegiant (true ULCCs with rock‑bottom base fares but many ancillaries). (thepointsguy.com, worldairlineawards.com)
• Asia / Pacific: AirAsia, Scoot, Jetstar, HK Express, VietJet — excellent intra‑Asia coverage and very cheap fares on many short hops. (skytraxratings.com)
• Middle East: flynas, flydubai — growing LCC options connecting regional and some international routes. (worldairlineawards.com)
• Latin America: JetSMART, SKY Airline (and other regional LCCs expanding routes across South America). (worldairlineawards.com, reuters.com)
• Africa: FlySafair, Fastjet, LIFT (FlySafair has earned top on‑time / low‑cost recognition in Africa). (travelnews.co.za, news.flysafair.co.za)

Long‑haul budget options

• Scoot and Jetstar are the most notable long‑haul/medium‑haul LCCs; these can save a lot on trans‑regional trips but check seat comfort and baggage policies. (skytraxratings.com)

Quick tips for flying budget airlines

• Compare "total price": include checked baggage, carry‑on rules, seat selection, priority boarding, and change/cancellation fees. (ULCC base fares are often tiny but ancillaries add up.) (thepointsguy.com)
• Book early on popular routes and watch flash sales — many LCCs run very cheap limited‑time fares. (wowfare.com)
• Check seat pitch and aircraft type for longer hops (some LCCs use narrow‑body jets on longer sectors). (skytraxratings.com)
• Safety & punctuality: most large LCCs meet standard safety audits, but on‑time performance varies by carrier/region — check recent OTP/safety reports for your specific airline/route. (cntraveler.com, news.flysafair.co.za)

If you want, I can:

• Make a short shortlist based on your route (example: U.S. → Europe, within SE Asia, etc.), or
• Compare total expected cost for two or three carriers on a specific route/dates.

Which region or route are you thinking about? (I can tailor tips or compare carriers and total costs.)