Though the spending cuts are scheduled to go into effect on Friday, furloughs of controllers won't kick in until April because the Federal Aviation Administration is required by law to give its employees advance notice.

NPR: How Budget Cuts Could Affect You

By law, the unions have to give seven days' notice of when the action will take place.

BBC: Post office counter staff vote to strike

Iran would almost certainly give the required 90 days notice of its intention to quit the Nuclear Non-Proliferation Treaty and terminate inspections by the International Atomic Energy Agency.

CNN: What if Israel bombs Iran?