Via British Airways and Starwood Starpoints

For every 20,000 Starpoints converted into British Airways miles through March 31, Starwood will award not only the standard 5,000 bonus miles, but also a special bonus of another 30% with BA—a fantastic promotion now in its third year by my calculations.

To qualify, you must be an existing Starwood Preferred Guest member, a British Airways Executive Club member, and a resident of the US, Canada, or Bermuda. BA miles post in about 4 to 6 weeks. Call (888) 625-4988 or log into your account to transfer.

Use this promotion to score a domestic Business Class ticket for only $327 more r/t on American

Here’s how to play it: Convert 25,000 Starpoints into 30,000 BA miles and net the limited-time 30% (9,000 miles) bonus. Then, you only need 11,000 BA miles for the upgrade, which you can purchase directly from British Airways’ website (for $327) to get to 50,000. That’s the number of BA miles it takes to get a free Business Class ticket on American, domestically. This can save as much as $1,500 off normal fares.

Europe Business Class upgrades for $420

Use British Airways miles to fly BA or one of its Oneworld partners (Iberia, American, or Finnair) to many European cities in economy (50,000 miles) or Business (100,000 miles). With this promotion, 50,000 Starpoints net 77,000 BA miles. Convert just 12,000 more Starpoints at the same time (otherwise available for purchase for $420), and with the 30% bonus you’ll have 100,000 miles, enough to fly Business Class on any of the aforementioned carriers.

Asia Business Class upgrades for $420

Similar to the Europe upgrade strategy, 100,000 British Airways miles can net Business Class travel to Asia, with its Oneworld partner, Japan Airlines. Again, with this strategy, 50,000 Starpoints net 77,000 BA miles. Convert just 12,000 more Starpoints at the same time (otherwise available for purchase for $420), and with the 30% bonus you’ll have the 100,000 miles required to fly from one of Japan Airlines’ five US gateways.