As with all mileage runs, do your own research first!!
I flew courier twice several years ago between Miami and Madrid on Iberia. Worst flights of my life and only saved about $100-200 (charged 2 different prices in same month). Although miles could be eanered, the passenger name on the ticket was LHS Courier and not in my name= thus no miles on second trip and only 30% AA miles on first.
What to watch out for:
Some couriers disclose which airline you will be on and others tell you whether or not you earn FF miles.
In other courier flights, upgrades only come if overbooked so donīt expect it as a right.
Best courier deals are to Asia, ie. the article mentioned the person got to travel JAL with a paid overnight in Tokyo. The free layover and paid hotel is worth $$$ as you generally canīt put this in on a discount mileage run.
If you are flexible and looking to save money, go courier. If you are looking for multisegments and prefer flying JFK-MIA-LHR r/t instead of JKF-LHR as courier, go with booking online. Great deals are out there, you are not restricted to carry on luggage and can return with your dates instead of say a 21 day stay.
I may not be a good fan of couriers however I still keep it in my list of mileage run opportunities just in case as occasionally an offer to good to resist may pop up. It is all about supply and demand and when they canīt put people in seats, they offer incentives- ie. drop price, waive registration fee, allow 1 piece checked luggage, change of return date, etc.
Good luck and happy flying.
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"Fly me to the moon and let me earn alot of miles."