As just one example, a modern carrier like the Jefferson required at-sea replenishment of expendables every two to three weeks.

American carriers require more than double that travel for a free trip.

The problem became so large that some carriers required the use of a PIN before making calls.

However, the digital carriers require the bandwidth to be widened, which would cause interference to stations on the first adjacent channel.

Conventional carriers do not require pre-reservation.

Many potential invasives or carriers for invasives require permits and quarantine periods before entry to the state is allowed.

However, despite manufacturer acceptance, some carriers in the US still require that phones are locked down.

Most carriers require older passengers to provide a physician's report of sound health before passage can be booked.

The carrier now requires passengers to pay a $25 surcharge for bags heavier than 50 pounds (previously, the maximum free weight had been 70 pounds).

In their turn, the carriers became prime targets and required more heavily protected and complex operations to ensure success.