Gun smuggling busted

Alleged smuggling ring said to have used commercial airline flights to get guns to New York City.

From the Atlanta Journal Constitution:

Police say more than 150 guns were illegally smuggled from Atlanta to New York on more than a dozen trips. Channel 2's Rachel Stockman broke the news Monday that a former Delta employee at Hartsfield-Jackson is accused of using his clearance to help smuggle the guns.  

Investigators believe those guns made it on to 20 different flights. 

Why fly? Seems a terribly complicated and risky way to move contraband.

Wouldn't have driving been safer, with less chance of detection, and also allowed for bigger loads?