In this riddle, what has wheels and flies, but is not an aircraft?

Introduction / Context:
This riddle uses a pun on the word flies. At first glance, wheels and flies makes you think of something that moves through the air, such as an aircraft. However, the puzzle explicitly says it is not an aircraft, which forces us to look for a different meaning of flies. The common answer is a garbage truck, which has wheels to drive on roads and flies, the insects, attracted by rubbish.

Given Data / Assumptions:

• The object has wheels.
• It also has flies.
• It is definitely not an aircraft.
• Options include a garbage truck, a helicopter, a delivery van, a fire engine and None of these.
• We assume flies can mean insects and not only the verb to fly.

Concept / Approach:
The trick is to recognise the double meaning of flies. As a verb, flies suggests movement through the air. As a noun, flies refers to insects often seen near waste. Garbage trucks have several wheels and tend to carry rubbish, which attracts many flies. Therefore they satisfy both conditions without being any kind of aircraft. Other vehicles like delivery vans and fire engines have wheels but are not typically linked to swarms of flies in a standard riddle context.

Step-by-Step Solution:
Step 1: Identify that wheels suggests some kind of land vehicle. Step 2: Remember that flies might mean insects that gather around trash or decaying material. Step 3: Think of common vehicles that are strongly associated with rubbish. Step 4: A garbage truck is a large vehicle that collects waste from homes and businesses. Step 5: Rubbish in or near a garbage truck often attracts flies, especially in warm weather. Step 6: The garbage truck clearly has wheels and is often surrounded by flies but does not fly itself. Step 7: Therefore A garbage truck is the logical and traditional answer.

Verification / Alternative check:
Check the other options. A helicopter does fly, which conflicts with the statement that it is not an aircraft. A delivery van and a fire engine have wheels but not usually a notable swarm of flies associated with them, at least not as part of a standard riddle. None of these is incorrect because the garbage truck option fits perfectly. This confirms that the puzzle is using a common play on the noun flies rather than focusing on the verb to fly.

Why Other Options Are Wrong:
A helicopter: It is an aircraft, directly contradicting the condition in the riddle.
A delivery van: It has wheels but no typical link to flies, so it does not exploit the wordplay.
A fire engine: It is associated with emergencies and water, not rubbish and insects.
None of these: This is incorrect because a garbage truck fits the description exactly in a widely used riddle.

Common Pitfalls:
Many learners initially think in terms of speed or flying machines and choose helicopter before reading the last part of the question carefully. Others may not switch to the insect meaning of flies and thus struggle to find any reasonable candidate. Riddles frequently depend on such double meanings, so it is important to ask yourself whether a word could be a noun or a verb with very different implications. Recognising that flies are insects makes the answer straightforward.

Final Answer:
The thing that has wheels and flies but is not an aircraft is a garbage truck.