air sandwich

noun2

1. •
   (informal) A sandwich consisting only of bread and optionally a spread, but no filling.

   • Glancing into his wallet, he had just enough to cover it and a tad left to make it through the day's expenses, providing he had an air sandwich and glass of water for lunch. — 2005
2. •
   (informal, disapproving) A strategy that has high-level direction and low-level operations, but little in the middle.