1. broadcasting.

Channel 4 stayed on the air all night to cover the breaking news.

2. being broadcast.

At least for this season the program will still be on the air.

• a ripple effect
• a rite of passage
• armed to the teeth
• a road hog
• a roller coaster
• a roll in the hay
• a roof over head
• a roof over your head
• a rotten apple
• a rough diamond
• a rough ride
• around and around
• around ears
• around someone's ears
• around-the-clock
• around the clock
• around the corner
• a roving eye
• arrive at
• arrive at something
• arse about face
• arse-kisser
• arse-licker
• arse over tip
• arty-farty