Yes. US Airways does have a 24 hour cancellation policy. You must call 800-428-4322.

From US Airways:
24-hour refund rule

US Airways allows you to cancel any ticket (refundable or non-refundable) for a full refund (and no change fees and/or difference in fare) for up to 24 hours after purchase.

Call 800-428-4322 to cancel and request your refund!