The Wood Elf gets the 'Fleet of Foot' racial ability which states: "Your base walking speed increases to 35 feet."
Does this +5' increase in land speed carry over to any Wild Shapes?
Yeah, you get to keep it.
Check the SRD on wildshaping:
You can stay in a beast shape for a number of hours equal to half your druid level (rounded down). You then revert to your normal form unless you expend another use of this feature. You can revert to your normal form either by using a bonus action on your turn You automatically revert if you fall unconscious, drop to 0 hit points, or die. While you are transformed, the following rules apply:
You retain the benefit of any features from your class, race, or other source and can use them if the new form is physically capable of doing so. However, you can't use any of your special senses, such as darkvision, unless your new form also has that sense.
I've snipped some parts and added some emphasis, but you get to keep racial benefits if the new form can use them. That includes Fleet of Foot.
Yes. The relevant rule is:
You retain the benefit of any features from your class, race, or other source and can use them if the new form is physically capable of doing so.
However, this is not +5 to speed, it is a 35 foot speed so you get the creature's speed or 35 foot whichever is greater providing "the new form is physically capable of doing so." A DM might justifiably rule that a tortoise is not physically able to use the wood elf's speed.
Of course, this applies to the speed of all races, not just wood elfs.
RAW, you could certainly make the case that you keep it. The other answers do a good job of explaining why. However I highly doubt this is the intention.
Wild Shape says "Your game statistics are replaced by the statistics of the beast..." Given that Fleet of Foot is a racial trait and was not worded as a +5 speed increase, I'd argue Fleet of Foot defines what the speed for a Wood Elf is, and that this speed is replaced when you transform:
There's already some precedent for this; modifiers to your max HP don't carry over either for the same reason:
And then of course there's the fact that allowing Fleet of Foot as written gives implausible results with creatures like owls and bats.
That said Crawford himself says when talking about Wild Shape in the Dragon Talk podcast that some of the rules are written "in the spirit of cooperation" between the players and the DM, and Wild Shape is one of those. In the name of fun, a DM could turn a blind eye to the way Fleet of Foot is written and let the Druid increase their land speed by 5 while Wild Shaped.
I suspect Fleet of Foot, like Mask of the Wild, is meant to have a supernatural aspect to it, since Wood Elf anatomy doesn't appear to be much different from other elves. If a Dragonborn can keep their Breath Weapon while Wild Shaped, I don't see why Wood Elves shouldn't derive some benefit from Fleet of Foot.