Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Category | Speed\n(km/h) | Speed\n(mph) | Vehicle | Pilot | Date |
| --- | --- | --- | --- | --- | --- |
| Rocket-powered aircraft | 7,258 | 4,510 | North American X-15 | William J. Knight | 3 Oct 1967 |
| Manned air-breathing craft | 3,530 | 2,194 | Lockheed SR-71 Blackbird | Eldon W. Joersz | 28 Jul 1976 |
| Propeller-driven aircraft | 870 | 541 | Tupolev Tu-114 | Ivan Soukhomline | 1960 |
| Piston-engined propeller-driven aircraft | 850.1 | 528.33 | Grumman F8F Bearcat Rare Bear (N777L) | Lyle Shelton | 21 Aug 1989 |
| Helicopter | 401.0 | 249.1 | Westland Lynx 800 G-LYNX | John Egginton | 11 Aug 1986 |
| Glider (sailplane) | 306.8 | 190.6 | Schempp-Hirth Nimbus-4DM | Klaus Ohlmann and\n Matias Garcia Mazzaro | 22 Dec 2006 |
| Human-powered aircraft | 32 | 19.8 | MIT Monarch B | Frank Scarabino | 1 May 1984 |
Question:
what is the least fastest aircraft?
Answer:
Human-powered aircraft