The differences between the two jets mainly come on the top and rear of the builds. One has a larger single rear fin and two larger wings at the back, while the other has two smaller fins and the large wings positioned in the middle of the vehicle. The nose and cockpit areas are identical on both jets, and both come with stickers; the airshow logo on the wings, and a plane motif on the sides.
Manufacturing of Lego bricks occurs at several locations around the world. Moulding is done in Billund, Denmark; Nyíregyháza, Hungary; Monterrey, Mexico and most recently in Jiaxing, China. Brick decorations and packaging are done at plants in Denmark, Hungary, Mexico and Kladno in the Czech Republic. The Lego Group estimates that in five decades it has produced 400 billion Lego blocks. Annual production of Lego bricks averages approximately 36 billion, or about 1140 elements per second. According to an article in BusinessWeek in 2006, Lego could be considered the world's No. 1 tire manufacturer; the factory produces about 306 million small rubber tires a year. The claim was reiterated in 2012.
The programmable Lego brick which is at the heart of these robotics sets has undergone several updates and redesigns, with the latest being called the 'EV3' brick, being sold under the name of Lego Mindstorms EV3. The set includes sensors that detect touch, light, sound and ultrasonic waves, with several others being sold separately, including an RFID reader.
In contrast to the first jet with its delta wing configuration and forward canard wings, the second jet features a more conventional straight wing configuration with tapered leading and trailing edges. As you might expect, construction of the fuselage of the second jet is in many ways similar to that of the first, although in order to accommodate twin exhausts the rear isn’t tapered, and the air intakes which flank the fuselage are of a different design.
Since 1963, Lego pieces have been manufactured from a strong, resilient plastic known as acrylonitrile butadiene styrene (ABS). As of September 2008, Lego engineers use the NX CAD/CAM/CAE PLM software suite to model the elements. The software allows the parts to be optimised by way of mould flow and stress analysis. Prototype moulds are sometimes built before the design is committed to mass production. The ABS plastic is heated to 232 °C (450 °F) until it reaches a dough-like consistency. It is then injected into the moulds at pressures between 25 and 150 tonnes, and takes approximately 15 seconds to cool. The moulds are permitted a tolerance of up to twenty micrometres, to ensure the bricks remain connected. Human inspectors check the output of the moulds, to eliminate significant variations in colour or thickness. According to the Lego Group, about eighteen bricks out of every million fail to meet the standard required. Lego factories recycle all but about 1 percent of their plastic waste from the manufacturing process. If the plastic cannot be re-used in Lego bricks, it is processed and sold on to industries that can make use of it. Lego has a self-imposed 2030 deadline to find a more eco-friendly alternative to the ABS plastic it currently uses in its bricks.
The final two minifigures are the Biplane Pilot and the intrepid Wing Walker. Both of these minifigures share the same white torso which is printed with a flight suit design overlaid with dark red and bright light orange flames plus a logo over the left breast. The torso design is superb and it can at present only be found in this set. Both minifigures are provided with a reddish brown aviator cap and dark bluish grey goggles, and the pilot (below left) also gets an alternative to this headgear in the form of medium dark flesh mid-length hair which has only ever appeared in five sets in this colour.