Disney Answer: Maybe
Each night in the Magic Kingdom and Disneyland, Fantasyland (or parts of it) is closed for the nightly fireworks show that happens on and around Cinderella’s and Sleeping Beauty’s Castles. While all of Fantasyland in Disneyland is closed during the fireworks, only the part between Prince Charming Regal Carrousel and Cinderella’s Castle is closed in the Magic Kingdom, while many of the rides behind the carousel will remain open during fireworks. This really is unfortunate for many as a large part of the park must shut down hours before the normal closing time. However, some nights, Disney will reopen Fantasyland after fireworks.
The answer to the Disney question really depends on park hours. If there is enough time after the fireworks end, then Fantasyland will open back up. If the nightly fireworks are towards closing time, then of course, Fantasyland will not reopen until the next morning. I have found that if the fireworks start 2 hours or more before park closing, then Fantasyland will reopen. Once you get inside that 2 hour window, it really doesn’t make sense for Disney to reopen a large part of the parks just for a few minutes.
The current Magic Kingdom fireworks show “Wishes” is a 12 minute show, while the current Disneyland show “Remember…Dreams Come True” is closer to 16 minutes long. It takes quite a while for Disney to clear Fantasyland after the fireworks, but you can expect Fantasyland to be open sometime around 15 – 30 minutes after the fireworks end, and it should remain open until park closing.
Tonight in the Magic Kingdom, Wishes is scheduled for 9:00 PM, and the park is open until 11:00 PM, so you should have access to Fantasyland for a bit over about 90 minutes after it reopens.
Please note: Currently, Disneyland DOES NOT offer fireworks during the week, they are only allowed to present their fireworks show on weekend nights (Friday, Saturday and Sunday nights), so Fantasyland will remain open all night on weekdays.
DisAnswers Hint: If you want to ride Peter Pan, head to the back side of Fantasyland in Disneyland right after the fireworks open. Disney will start a line for Peter Pan near Mr. Toad’s Wild Ride, and will only allow about 50 people in the line. Once Fantasyland is ready to open, they will escort that line to Peter Pan and start loading the ride. Once that line is in place, they will drop the rope and allow everyone else into Fantasyland.