Say you searched "hkexpress" this morning because someone sent you a HK$77 fare to Hefei. You click through and the number is gone. The sale ran from 10:00 on 30 September to 23:45 on 4 October. You missed it by a few hours.

The announcement does not list post-sale fares. The HK$77 was a round trip, "Ultra Lite", with one small personal item. Anything bigger costs extra.

The flight itself is real. Four a week to Hefei, the capital of Anhui, on Tuesdays, Thursdays, Saturdays and Sundays. About two and a half hours on an A320neo. First flight is 3 December, and the airline says the route is subject to regulatory approval.

Wego priced an early December sample after the fact: US$128 return from Hong Kong. China Eastern's nonstop, which flies Mondays, Wednesdays, Fridays and Sundays, was US$178. So the budget carrier still wins by US$50, just not by the margin on the poster.

Between the two airlines there is now a nonstop to Hefei every day of the week. Pack small, check the price on the day, and wait for 3 December to see if the approval comes through.