Mailing from coast-to-coast sounds like it would take a long time, but there are regular flights cross-country, and the sorting facilities bring mail to the middle of the coast, and then ship it straight across, east or west, depending. This means that the mail has to go first to a central sorting facility.
Truck and bus drivers must generally take a minimum of eight hours off between shifts, and their shift hours are often capped. Airline pilots are required to have 10 hours off between shifts to allow for transportation and rest time.
Employers must authorize and permit one paid, 10-minute rest break for each four hours worked or major fraction thereof. If practicable, the 10-minute rest break should occur in the middle of each work period. The 10-minute rest break isn't required for employees whose total daily work time is less than 3.5 hours.