Continuity mistake: When Matilda makes the chalk write the message on the blackboard, the writing changes. Watch the "Agatha," especially. The handwriting changes and the comma changes length, as well as most of the message changing. Also at the end of the message Matilda "writes" two long lines under it, which cross over. Yet later when Miss Trunchbull flies off the globe you can see there is just one line under the message, not two. (01:20:20 - 01:23:00)
Continuity mistake: When Mrs. Waterhouse walks into the livingroom and greets her three babies, there is a large area rug in front of the coffee table. However, as the babies fly towards her in the wide shot facing her, that area rug is gone! (00:22:55 - 00:23:50)
Factual error: Casey arrives at the desert landing in a jeep that is flagged with 4 stars (for a 4 star general) although he is only a 3 star general (as evident by the 3 stars on his shoulder boards). (00:33:30 - 00:35:25)
Continuity mistake: Before Draco lifts up Bowen his grip on the cable changes between shots.