Divide the class into groups of five or six. Give each group a short bit of the history of flight to research. One group can look at the invention of balloon flight, another at Leonardo Da Vinci and his ideas, another at the Wright brothers, another at the moon landing. Have each group come up with a short play to explain the things they have found out to each other.
Break the class up into groups and run an airship endurance race. Show the class how to make simple propellers out of card. All tyou need for this is to bend the corners of a rectangular card. Have them build some very light gondolas from card. The gondolas need to hold an axle made from a bamboo skewer and a propeller driven by a rubber band wound around the axle. The gondola will suspend from helium balloons. Each airship may use up to six balloons. Aside from this, the design is up to the groups. The group that makes the airship that travels farther wins. Run the race inside if possible to avoid wind.
Get a book showing several designs of paper airplanes, or demonstrate them yourself if you know some good ones. Give the students an hour or so to learn how to make them, test them out and come up with their own modifications. After this, urge them to make the best airplane they can imagine. Have them all write their names on their airplanes, then take them up to a high building. If possible, get them all to throw their planes at once and see which ones go farthest. See if some designs are better than others.
Study the different ways that different creatures fly. Some can hover while others glide, hardly moving their wings. Split the class into groups and assign each a flying creature. Have them look at the way it flies and ask them to think about the reason it flies like that and not in another way. Get them to think about what kinds of flight need more energy, then get them to think about and research the adaptations that creatures have to help them fly. Get each group to make a poster about the animal they chosen