That may be true if you include flak units, which constituted about 2/3rds of total Luftwaffe personnel strength during the late 1930s. There were also hundreds of training aircraft as the Luftwaffe struggled to created pilots, aircrew and ground support personnel from scratch.
However if we count only modern fighter and bomber units capable of being deployed on combat operations then the pre-WWII Luftwaffe was tiny. For instance the Soviet Union sent about 475 modern I-16 monoplane fighter aircraft to Marxist Spain and some of them were in combat by November 1936. Germany had nothing similiar to offer the Nationalist side as the comparable Me-109 was not yet in mass production.
What each "sponsor" nation was willing to send to the Spanish civil War doesn't mean that they were sending forces in proportion to what was kept at home.
Every other nation was also struggling to create pilots, aircrew and ground support personnel.
Some of the British planes ordered and built in thirties were known at the time to be obsolete but were needed to give the newly raised squadrons something to use/ practice on while better designs were developed.
Why do you want to give only the Germans a pass on this?
See this web site.
Aircraft production - Parts 12
Please look at fig. 3.The Germans were making more aircraft in 1935, 1936 and in 1937 than another single country.
Please name other countries that had more modern fighter and bomber units Than Germany did in theses years? And the numbers of modern fighters and bombers that they had?
Why don't you look up the British Fairey Hendon, Handley Page Heyford, Boulton and Paul Overstrand, Handley Page Harrow, and the Vickers Wellesley and tell us how modern and up to date the were compared to the German bombers of 1935-39.
Or check out the Gloster Gauntlet, fastest plane IN SERVICE with the RAF in 1935-37 and equipping 14 fighter squadrons at it's peak. Or the Hawker Fury II which was still in front line service in 1939.
For France try looking at the Dewoitine D 500-510 series many of which were still in service in 1939 and replaced by the Morane-Saulnier M.S.406.
The Idea the Germany was "coming from behind" in the mid 1930s or had a "tiny" air force in the mid thirties is just not true.