Fairyland is, by and large, socially a parallel to pre-Enlightenment European nations. The feudal system is ingrained deeply into the populace and perhaps even into the land itself. The nobility are very rich, and typically spend their time running their estates, attending court and other functions, challenging each other to duels and trying to second-guess next season's fashion. The poor are very poor, and typically spend their time up to their arse in a muddy turnip field. This is the way things are, and probably the way things will always be.
Or, then again, possibly not. Though the faeries essentially slept through what in human terms was approximately 1750 to 1900, their world split off almost completely from the humans', that is no longer the case. The two worlds are once again beginning to leak into each other, and the human world is a very different place now than it was the last time they were in contact. Whilst certain human achievements, such as the Age of Reason and the Industrial Revolution, are firmly incompatible with fairyland, others - war, and political upheaval - are not. Little by little, faeries - commoners, mostly - are beginning to question the Way Things Are.
The scientific method is quite lost on the fae. What scientists do exist tend to be more of the Dr. Frankenstein persuasion, dreaming up strange and sometimes terrifying things. Their discoveries owe more to glamour and to luck than any deductive process or logical reasoning.
All told, the readily availability of glamour magic and the wide range of effects it can cause mean that the vast majority of faeries are simply disinterested in science, and it is often branded as useless and banal.
The Problem of Iron
Iron is anathema to the fae, it barely exists in fairyland and is not used by any but the maddest of mad scientists. A large proportion of human technology relies upon iron and its derivatives. Fairyland has broadly kept apace up until about the technology level of the Middle Ages by using different materials. Tools, farming implements, weapons and armour may be made of a number of materials, depending on the social class of their owner.
Equipment used by the peasantry tends to be made from natural materials such as wood or stone, though bronze, copper and brass are also common. The nobility often have items made from more exotic materials, such as silver, gold, glass or even items made purely from glamour. For some reason, what would seem to be obvious problems with brass ploughs and gold armour never really seem to crop up.
Chemistry has not yet evolved from alchemy in fairyland, and even alchemists are rare. Consequently, gunpowder has not been invented and the most advanced ranged weapons remain the longbow and crossbow. The pistol, musket and cannon - and likewise the social and military changes they precipitated in the human world - have not made an appearance.
Fireworks do exist, but they are creations of glamour.
Travel between Worlds
Items passing from one world to another suffer ill effects if they rely on something that is not widely believed in. This is a problem whether one is travelling from the human world to Fairyland or the other way around.
Human technology that is beyond the understanding of faeries will not work in Fairyland. Mobile telephones will refuse to work, guns will refuse to fire, and even material changes will occur - plastics, for example, are not a feature of Fairyland and will thus revert to something else.
In Fairyland, magical items are very common. Any amulets, magic rings and so on that pass from Fairyland to the human world will also - by and large - not work.
There are ways around these problems. For a human item in Fairyland, one simply has to convince the fae of what something is and how it works. It may help to alter the truth slightly - explaining gunpowder is likely to be a non-starter, but explaining "magic exploding dust" would be much easier. However, it's a two-way process. Explaining it as magic exploding dust makes it magic exploding dust - it's not really gunpowder any more.
For a faerie item in the human world, one must overcome the humans' disbelief in magic. In keeping with the way rules are implemented in the game - i.e. there is much more expressive freedom in Fairyland, and much more rolling for stuff in the human world - this is done by overcoming the humans' Banality.