Short answer — there’s no single “most reliable” low‑cost carrier (LCC) worldwide; reliability depends a lot on the specific route, airport pairs, time of year and whether you mean on‑time performance, cancellation rate, or baggage/service reliability. That said, these LCCs have generally earned strong reputations for short international trips in their regions:

• Europe

  • easyJet — strong network across short European routes; generally good on‑time performance on busy point‑to‑point sectors.
  • Vueling — good for Spain‑centered short hops (Barcelona/Madrid hubs).
  • Wizz Air — wide CEE network and improving punctuality on many routes.
  • Ryanair — huge route map and often punctual, but customer‑service experience varies.

• Middle East / South Asia

  • IndiGo — India’s largest LCC; noted for high punctuality and very reliable short international services to nearby countries.
  • Air Arabia — focused on short international hops from the UAE region; generally consistent.
  • flydubai — operates many short international flights from the UAE with solid on‑time records.

• Southeast Asia / Australasia

  • AirAsia (and affiliate airlines) — extensive regional network; performance varies by country unit but widely used for short international hops.
  • Scoot / Tigerair (where applicable) and Jetstar — popular and reliable for short regional legs in Asia / Australia.

• North America / Caribbean / Latin America

  • Southwest (hybrid LCC) — very reliable on many short international routes to Mexico/Caribbean.
  • Volaris / VivaAerobus — Mexico’s LCCs have expanded short international services; reliability can vary by airport.
  • (Note: some Latin American ultra‑LCCs have had turbulent periods — check recent status for the specific carrier.)

How to judge reliability for your trip

• Use recent on‑time/cancellation reports. Independent sources: Cirium, OAG and national aviation authorities publish punctuality and cancellation stats. These change year‑to‑year.
• Check route‑specific performance. An airline can be excellent on some short hops and poor on others.
• Consider the airport(s). Smaller or congested airports, or those affected by strikes/weather, increase disruption risk.
• Prefer nonstop point‑to‑point flights. LCCs tend to be less forgiving with missed connections.
• Look at customer reviews for baggage, refunds and irregular‑operations handling (Skytrax, SeatGuru forums, Google reviews).
• Check financial/operational stability — airlines under financial pressure tend to cancel more.

Practical tips to reduce risk

• Book morning flights (less knock‑on delay from earlier flights).
• Avoid tight connections when flying LCCs.
• Pay a little extra for priority boarding/seat selection if that prevents long boarding delays or gives access to earlier/priority handling.
• Buy travel insurance that covers cancellations and delays, or use a credit card that offers delay protection.
• If you want, tell me your origin and destination (and travel dates) and I’ll check recent on‑time/cancellation performance and give a ranked recommendation for that route.