Regarding the plane built by Hiram Maxim, there is an article in the french journal L'Aeronaute from Nov. 1894. The author describes this huge plane and mentions the good reviews it received in newspapers but he does not clearly write Maxim's plane flew or at least made short hops, beyond any doubt.
"Il y a, dans les essais de M. Hiram Maxim, quelque chose de nouveau, c'est, l'emploi de deux rails superposés l'un au-dessous des roues, l'autre au-dessus. On met de la couleur sous le rail supérieur et si la couleur est enlevée, on déclare que l'appareil s'est envolé. Je trouve l'expérience mal faite. Il se peut très bien que l'aéroplane, qui a une très mauvaise stabilité, se renverse et qu'une des roues se soulève sans que pour cela l'appareil se soit enlevé. Il se peut encore que, comme l'aéroplane de M. Tatin, celui de M. Maxim fasse des bonds sans se maintenir en l'air et sans être capable de s'envoler."
(Source: "LE BREVET DE L'AÉROPLANE de M. HIRAM MAXIM" L'AÉRONAUTE, 27° ANNÉE. — N° 11. — NOVEMBRE 1894, L'Aéronaute (Paris) )
Translation:
"There is, in the trials of Mr. Hiram Maxim, something new, it is the use of two rails one below the wheels, the other above. The upper rail has paint and if the color is removed, we declare that the plane rose. I find the experiment badly done. It may well be that the airplane, which has a very poor stability, tends to overturn and one of the wheels lifts off without us being able to say the plane as a whole got in the air. It is still possible that, as the airplane of Mr. Tatin, the one of Mr. Maxim makes hops without staying in the air and without being able to fly."
It is not clear at all that Maxim's plane made even short hops, this is, it left the inferior rail with all the wheels for an instant. It might have left the lower rail with both left and right front wheels, a case for which the paint from the upper rails would have been removed. The force could have even broken the superior rail without the back wheels being able to quit the lower rail.
Hiram Maxim definitely had a plane in 1894 but the publications of the time do not confirm 100% a true take off (all wheels simultaneously not in contact with the lower rails).