How can I make sure a driver is available at the Manchester NH airport when I land?

It's up to availability when you land. However, at airports, you have good odds.

If you are referring to rideshare services like Uber, the availability of the ride is dependent on the driver availability.  Since the drivers decide their own hours and locaiton, there is never a guarantee they will be at the airport when you arrive.

With that said, the chance is good that there will be an Uber when you land, because airport pickups and drop offs are usually very lucrative.  Good passengers, generally longer rides, good tippers, consistent customers, etc.    So unless you are landing at a very odd hour such as 3:30AM on a Wednesday, you should be good.

If you want to make sure there will be someone there,  you can reserve a ride with a local taxi or a limo company. 

ippei 1202

Uber Driver, CEO of TaxiFareFinder and Unleashed, LLC