A lot of the Afghan refugees are still in Afghanistan. This makes any form of food delivery difficult and dangerous. Until whatever air defenses that exist in Afghanistan are neutralized, it'd be dangerous to perform airdrops. Transport planes don't carry much in the way of electronics countermeasures against radar guided missiles. The C-17 does carry flares to attempt to divert IR missiles but that's about it. They aren't maneuverable enough or fast enough to evade a missile so large scale airdrops inside Afghanistan will have to wait.

Airdrops are expensive so the preferred method of delivering food is via truck convoy. However, there aren't many roads in Afghanistan and many of them are vulnerable to attack. The Taliban has expelled most relief workers, so distributing the food is a real challenge. Odds are the food would just be confiscated by the Taliban for their own use. About the best we can do in the near term is to airdrop supplies in safe regions near the borders and to truck in supplies to refugee camps in Pakistan. Many of the refugees have also fled to other countries like Iran. We don't have diplomatic relations with Iran and they've condemned our attacks, so getting relief supplies to those refugees will be difficult.