describes a situation which is uncertain:
The doctor says that it's touch-and-go whether Mary will be okay.
verb intr.: To fly close to the ground.
intr.v. flat-hat·ted, flat-hat·ting, flat-hats
To fly an airplane close to the ground and at a high or dangerous speed.
From the allusion to a plane flying so low as to flatten a hat on someone's head. Earliest documented use: 1940.
"Those impromptu flights often took him only feet above the beach on Cumberland Island where he'd practice 'touch-and-go's and flathatting." — Scott Keepfer; Record Still Stands After 75 Years; The Greenville News (South Carolina); Jun 24, 2007.