However, if you are tracking a red dragon's footsteps and they suddenly end by it took flight...
conjure animalss to summon birds and have them fan out
speak with animals and ask if they've seen it
speak with plants to ask the trees which way it went
locate creature if you know it
locate object if you have one of it's possessions
use you crystal ball (1st edition level 9 ranger feature) to scry it.
The problem with that is that those spells are generally pretty situational, and 5e rangers are spells-known casters. Spells-known casters tend to choose most of their spells for the widest possible utility, rather than narrow applications.
And that leads me into one of the two changes I'd make to the 5e ranger: I would make them prepared casters instead, like paladins. IMO, that works a lot better with the "wilderness scout" feel of the class - they try to learn things about the situation they would be in, in order to bring the right toolkit (= spells prepared). I might expand their spell list a little to help with that - there are probably some druid spells that were judged too situational to put on the ranger list where they'd act as traps.
The second change I'd make would be to the Beastmaster, where the animal could act independently of the ranger. That might require a nerf of the companion, but I feel it's the right thing to do. The thing is that the Hunter gets to
add damage compared to the baseline ranger in various situations (when attacking wounded targets, when attacking packed targets, or when being attacked by big creatures), whereas the Beastmaster gets to
replace some of her regular damage with the companion's damage. A Colossus Slayer hunter with a longbow and Dex 18 (at 4th level) will attack once at +6 and deal 2d8+4 against a wounded target (and there usually is a wounded target around to shoot). A Beastmaster with the same stats and a Wolf companion can either attack herself once at +6 for 1d8+4, or get their wolf buddy to do it at +6 for 2d4+4 with a relatively easy save to avoid getting knocked prone. In addition, the ranger has a lot more options for enhancing their own attacks (various spells, stat increases, feats) than those of their companion - though the companion does get a bit of a buff via proficiency bonus on its own, but hardly enough to make up for things like
hail of thorns or Sharpshooter.
On the other hand, writing that does give me an idea for a niche for the Beastmaster: the "survivalist" ranger. This is, the ranger that
doesn't take feats and spells that make them better in personal combat, but instead focuses on knowing more stuff about the wilderness. More
speak with animal,
water breathing, and
locate creature than
hail of thorns,
lightning arrow, or
conjure barrage. The companion doesn't have as many opportunities for buffing, but it does get a little buffer on its own, and that lets the ranger do other stuff. I don't know how viable this is, but I think it's a better way to work the Beastmaster instead of focusing on damage.