Error when appending object to empty array

I am trying to form an array of a particular type of object, specifically the output model from fitdiscr, ClassificationDiscriminant.

Right now I am trying to do the following way:

model_cache = []
for i = 1:10
model = fitdiscr(...)
model_cache = [model_cache; model];
end

But this gives me the error

Undefined function 'throwNoCatError' for input arguments
of type 'double'.

Error in
classreg.learning.internal.DisallowVectorOps/vertcat
(line 49)
        function a = vertcat(this,varargin),
        throwNoCatError(this); end

Error in main_crossvalidate_sessions (line 84)
    model_cache = [model_cache;model];

Which in plain english means I cannot concatenate a double with an object ([] is a double). How do I solve this issue? The way I can think of is ugly - when i = 1, model_cache = [model]; then in subsequent iterations append as usual. Are there simple solutions?

[Liyuan]

Seems possible to do with cells, but I'm still curious, is there any way to do this with arrays, like an array of structures?