two planes intersect in one line, or the planes could be parallel. by the way there is no such thing as skew planes...
parallel planes
There is no "the" since there are infinitely many non-parallel planes. Two non-parallel planes are planes that intersect in a line.
The angle between two planes when the planes intersect at a point is the acute angle fixed by the normal vectors of the planes.
Two planes intersect (not interscept) at an edge (or a line).
float and pressure
I don't know which two classifications you are referring to, but the two most common are 100LL Avgas, and JET-A. The first is used in piston engines (like a car's) found in small prop planes ; 100 is the octane rating, and the LL means Low Lead. JET-A is used in turbine engines found on larger prop planes and on planes with turbojet engines; JET-A is similar to diesel fuel, it is just a higher quality for use in aviation.
The two main types of rocket engines are Solid fuel rocket engines and Liquid fuel rocket engines.
cross flow, loop, and uni-flow.
There are two types of search engines 1. Hybrid search engines 2. Meta search engines
Typically the two types of engines deployed in the modern hybrid car is a small gasoline engine combined with an electric engine.
If a given plane has four engines, they are all used and needed to carry out a normal flight. It is absolutely uncommon to shut down engines inflight. On the ground at taxi-in or taxi-out, one or two engines can be shut down to save some fuel. A four engined aircraft can actually fly on only two engines in some cases (though only if the other engines have failed)
Mesaba Airlines uses planes in the CRJ family. The two most used planes by Mesaba Airlines (and related company Pinnacle Airlines Inc.) are the CRJ-900 and the CRJ-200 LR.
search engines and directories
There are basically two types of spark ignition engine. They are the diesel spark engines and the petrol spark engines.
Actually, it would make more sense to ask who created the helicopter. As designs and ideas for helicopters have evolved throughout the years, one thing has remained the same-there is no one specific engine that has been created strictly for a helicopter. Helicopters use engines that can be used for other aircraft such as planes, jets and turboprops. They can be factory modified to fit a specific helicopter but the basic design remains used amongst many applications. Early helicopters used engines that were already being made for airplanes. Modern helicopters use two basic types of engines-piston and turbine. Piston engines are similar to ones used in automobiles. Turbine engines, also known as jet engines, make a loud shireking whirring noise when they are operating. Both types are also used in airplanes.
internal and external combustion engine