Please choose the correct ending to complete the given sentence: Travel: [header] How to be safe while flying [title] Learn how to fasten your seat belt. [step] Insert the metal tip into the buckle until it clicks, then pull on the strap to tighten. To unfasten, lift on the flap of the buckle.

Ending1: To fasten, unbuckle the other side of the flap and gently brush the flap to dislodge any loose air. [title] Get comfortable in a small enclosed area. Ending2: Make sure it's securely fastened before you fly using a piece of airplane rubber ring or small, stiff rubber tubing. There are two ways to secure a buckle in a properly fastened seat belt. Ending3: You should feel it click into place and the hem of the seat belt should come loose with enough force to keep the aircraft from tipping forward. Drop the flap straight down so it's almost touching the ground. Ending4: [title] Fasten your seat belt whenever the " fasten seat belt " sign is lit. [step] During this period, it is dangerous to get out of your seat because of rough air or gravity.

Answer format: ending1/ending2/ending3/ending4