When flying to Valdez on a normal commuter airline you must first fly to the Anchorage(ANC) airport. From there you may take a flight with RavnAir to get to Valdez. They offer services to Valdez twice daily, with a morning and evening flight.
This is Alaska so it is possible to find a charter option to fly you to Valdez but one would need to do a lot of calling around to find a Part 135 Air Taxi.
Flights in and out of Valdez can be temperamental, and the planes flying in are smaller and subject to weather. Sequential multiple day cancellations are not infrequent. Cloud cover, fog, blizzards, and high winds are all able to close out flights to and from Valdez. There are no scheduled buses to Valdez to rely on for a backup.
If you are planning to fly out of Alaska from Valdez, book your flight from Valdez on the same purchase for your destination. If your flight is booked as one flight with a layover in Anchorage you should not be responsible for missing your Anchorage flight because of weather in Valdez. Your airlines should get you on the next available flight free of charge. If you book your Ravn flight separately your next airlines will expect you to pay a rebooking fee.
If weather is looking bad try and get on the Facebook Valdez Online Bulletin Board and ask about rides to Anchorage. If unable to hopefully you made a good contact with a local who can ask around for you. If your flight is canceled while at the airport ask around if anyone is driving to Anchorage if you can't afford to wait. It's considerate to pay for someone's gas if catching a ride. There are no chain car rental businesses in Valdez to rent a car and leave in Anchorage.
The flight between Anchorage and Valdez is 45 minutes and is usually accompanied with a cookie and drink.
This section of Alaska you pass over is dense with glaciers. Sit on the north side for glacier views and south for views of Prince William Sound and the islands. Though some days the clouds can stack up against the mountains there and it's clouds on both sides...