wide blue yonder

1. A faraway location that is appealingly unknown and mysterious. Typically used in the phrase "into the wide blue yonder." I often dream about selling all my possessions, buying a plane ticket to Europe, and setting off into the wide blue yonder.

2. old-fashioned The sky. I learned to fly a plane shortly after high school. I'm never happier than when I'm up in the wide blue yonder.

the wide (or wild) blue yonder

the sky or sea; the far or unknown distance.

The phrase comes from ‘Army Air Corps’ ( 1939 ), a song by Robert Crawford : ‘Off we go into the wild blue yonder, Climbing high into the sun’.