Short answer — there are a few commercial aggregator tools that will search live award availability across many airlines at once, and a set of airline/alliance websites that let you view partner (multi‑carrier) award space. The most commonly used are:

• Point.Me — a paid award‑search engine that searches dozens (they advertise 100+) of airlines and multiple loyalty programs in one query and shows live partner saver availability and booking instructions. Good for surfacing partner options you won’t see on one carrier’s site. (Point.Me)

• ExpertFlyer — a paid professional tool that can show award & upgrade inventory for many airlines and lets you query multiple carriers/award classes. Note: its access to some airlines’ award data has changed in recent years, so coverage is not universal. (ExpertFlyer.com)

• Airline/alliance booking engines (examples: Air Canada Aeroplan, United MileagePlus, ANA, Qantas, British Airways) — these are not third‑party aggregators but they let you view partner award inventory across alliance members (Star Alliance, Oneworld, SkyTeam members depending on the site). Using a couple of different alliance/partner sites is often the cheapest/free way to check multi‑carrier award availability. (awardwallet.com)

Other notes and tools people mention

• AwardHacker and similar “award ideas” sites are useful for plotting which program can book a route cheaply, but they do not reliably perform live multi‑carrier award availability searches (they’re recommendation engines rather than live seat scrapers). (awardwallet.com)
• AwardWallet is helpful to track balances and link to the right airline search, but it doesn’t replace a live cross‑carrier availability search tool. (awardwallet.com)

Quick practical advice

• If you want a one‑click, multi‑airline live search: Point.Me is the most explicit aggregator built for that purpose (paid). (Point.Me)
• If you prefer DIY and want to avoid subscription fees: search a couple of major partner/alliance sites (United, Aeroplan, ANA, Qantas/BA depending on alliance) — they will show partner seats in many cases. (awardwallet.com)
• Consider using both: an aggregator to find possibilities and the airline’s own site (or a call to the airline) to confirm and book, because some award inventory is withheld/restricted to the operating carrier. (connect.Point.Me)

If you want, I can:

• compare Point.Me vs ExpertFlyer in more detail (coverage, price, trial options), or
• check current coverage for specific airlines you care about (e.g., Qatar, Korean, Singapore) before you subscribe.