Aria

Aria was formed in Japan in 1953 by Shiro Arai as Arai & Co. and have been producing a range of instruments including Ukuleles since 1956. 

The very first ones sold were branded Arai sometimes with Land'o'Lei as well, but by the 1960's this had change to Aria. They changed style of lettering of the Aria in the headstock, (and sound hole label) branding a few times over the years but I don't have dates for the changes

Over the years they have had Soprano, Concert, Tenor and Baritone Ukuleles plus Guitaleles, a Uke Bass and a Banjolele in the catalogue. In the past the range was made in Japan, however the modern ones are made in China. 

They have introduced a range with a new logo and a rounded headstock branded Aria Ukulele Co. These are made of 3 ply laminate mahogany or koa that has been specially treated in a process they call T.L.S.B.™. There are Soprano, Concert and Tenor models.

They have also in the past branded a budget range of Chinese made colourful Sopranos called Ariana, though in 2013 they changed the name to Kapua. and have now changed again to Maika'i

 Aria have worldwide distribution for a range branded Laule'a . They look like standard Chinese made fair, Soprano, Concert and Tenor in laminate, (and apparently solid?), mahogany, koa and zebrano. They have a distinctive rosette, resembling a wreath, made from small holes cut around the central soundhole. I can find nothing on them apart from the Aria website so I suspect they are a subsidiary brand. 

Aria have also taken over worldwide distribution for, (so probably now own too), Keli'i and Pignose

Uilani (by Pignose)

This is an acoustic Ukulele branding that was used by Pinnacle Pacific Group Inc. before Aria took over. I don't know when it was started and I don't think it is still in use?