A flight search engine that combines flights from different airlines? (2014)

What the OP Is Really Asking About

• OP wants a flight search engine that combines flights from different airlines on separate tickets to create cheaper or more flexible itineraries.
• This is widely referred to as “virtual interlining” or “self-transfer,” distinct from traditional interlining on a single ticket.

Virtual Interlining & Example Tools

• Kiwi.com, Hopper’s “Mix & Match,” Skiplagged, and Tripstack’s tech are cited as implementing virtual interlining with some form of connection insurance/“layover protection.”
• Users report big savings (sometimes hundreds of euros/dollars, or large percentage discounts), especially within Europe and for budget carriers.
• Several people say they’d still avoid using it for “important” or time‑critical trips due to risk.

Risks of Separate Tickets & Third‑Party OTAs

• Key risk: if one leg is delayed, the onward airline has no obligation to rebook or refund; traveler is on their own financially and logistically.
• Checked baggage and irregular operations (IRROPS) become much more stressful; stories of being stranded, losing money, or stuck between airline and OTA blaming each other.
• Many contributors strongly prefer booking directly with airlines, using OTAs only for search; others in Europe report routinely booking through third parties with few issues and significant savings.
• Some describe particularly bad experiences with certain OTAs (e.g., hostile airline relationships, inability to use mobile check‑in, terrible support).

Search Engines, GDS, and Data Access

• Traditional Global Distribution Systems (Sabre, Amadeus, Travelport) were meant to be single sources of truth, but airline opt‑outs and fragmentation create gaps.
• Calls for an “uber‑GDS” / meta‑meta‑search are tempered by claims that economics don’t work: low commissions, high scraping/API costs, and users bypassing aggregators to book direct.
• ITA Software (now underpinning Google Flights and ITA Matrix) is praised for powerful search; Google Flights is widely liked but sometimes surfaces OTA‑only prices.
• Data access is hard: scraping low‑cost carriers is brittle and legally contested; comprehensive, up‑to‑date global inventory remains elusive.

Desired Features & Market Reality

• Users want: multi‑city optimization, “explore from this airport” views, multi‑origin searches, and better points/loyalty optimization.
• Several note that many sophisticated pre‑COVID “tricks” matter less now due to route changes, higher or restructured prices, and generally tighter networks.