Here are the best types of websites and specific sites you can use to search for and book flights with miles, plus a short note on what each does and when to use it.

Airline/loyalty program websites (best for booking award travel and partner awards)

• United MileagePlus (United.com) — excellent partner search; good for Star Alliance awards.
• Air Canada Aeroplan (aircanada.com) — great partner availability and mixed-cabin pricing.
• Avianca LifeMiles (lifemiles.com) — often shows saver-level partner seats and has good pricing.
• ANA Mileage Club (ana.co.jp) — great value for many partner redemptions (fuel surcharges vary).
• Singapore KrisFlyer (singaporeair.com) — good for partner redemptions and saver awards.
• Alaska Airlines Mileage Plan (alaskaair.com) — valuable for many partners (incl. international carriers).
• British Airways Executive Club (britishairways.com) — use Avios for short/one-way zone-based awards.
• American AAdvantage (aa.com) — best for Oneworld partner awards and American flights.
• Delta SkyMiles (Delta.com) — searchable award inventory, variable pricing.

Bank/credit-card portals and transferable points portals (use points instead of airline miles; some let you transfer to partners)

• Chase Ultimate Rewards portal — redeem points for travel or transfer to airline partners (e.g., United, Avianca, British Airways).
• American Express Membership Rewards — transfer to many airline partners or book through Amex Travel.
• Capital One Travel / transfer partners — book or transfer to partners like Air Canada, Avianca, Turkish.

Award-search tools & brokers (help find/compare award availability across programs)

• AwardHacker — quick idea of which programs have the award pricing/routes (estimating only).
• Point.Me (formerly Juicy Miles / AwardNexus) — paid service and tools to search award availability across carriers.
• ExpertFlyer — paid subscription for award/seat availability alerts and fare class data.
• AwardWallet — tracks miles and can show some award availability links.
• SeatSpy / Swoodoo-type tools — useful for specific airlines/routes (availability depends on region).

Specialty marketplaces & transfer/points marketplaces

• Points.com — track, exchange, and in some cases move/convert points between programs (limited).
• Cash + miles options: some airlines’ sites let you pay partly with miles and partly cash.

Quick tips for best results

• Start at the operating airline’s loyalty site (or its best partner) to actually book awards — partners’ sites sometimes show different availability/pricing.
• Use transferable points portals (Chase/Amex/Capital One) when you want flexibility or to top up an airline balance.
• Use award-search tools (AwardHacker, Point.Me, ExpertFlyer) to locate saver seats before transferring points.
• Beware of fuel surcharges and cancellation/change rules — those vary widely by program.
• If you’re searching for international premium cabins, also check on partner programs (e.g., ANA, Aeroplan, Singapore) which sometimes have lower prices.

If you want, tell me the airline(s), alliance, or route you’re interested in and whether you have specific miles/points (e.g., Amex, Chase, United, Delta), and I’ll list the best sites/programs to check and a recommended booking sequence.