The proper way is to redefine \and and use it. Anyways, the footnotemark is printed \rlapped in the \author, i.e. occupying no space. If we disable \rlap, everything works fine.
The "proper" code:
\documentclass{article}
\renewcommand\and{\end{tabular}\kern-\tabcolsep\ and\ \kern-\tabcolsep\begin{tabular}[t]{c}}
\let\origthanks\thanks
\renewcommand\thanks[1]{\begingroup\let\rlap\relax\origthanks{#1}\endgroup}
\title{The Title}
\author{Joe Bloggs\thanks{blah} \and John Smith\thanks{blah}}
\begin{document}
\maketitle
\end{document}
The code that only disables \rlap and does not modify anything else:
\documentclass{article}
\let\origthanks\thanks
\renewcommand\thanks[1]{\begingroup\let\rlap\relax\origthanks{#1}\endgroup}
\title{The Title}
\author{Joe Bloggs\thanks{blah}\ and\ John Smith\thanks{blah}}
\begin{document}
\maketitle
\end{document}
The output of both codes is exactly the same.
The report.cls defines the author portion of \maketitle to be a tabular array, that is
{\large
\lineskip .75em%
\begin{tabular}[t]{c}%
\@author
\end{tabular}\par}%
The default definition of \and from latex.ltx is used to end the tabular environment, add a bit of horizontal space, and then start a new tabular environment:
\def\and{% % \begin{tabular}
\end{tabular}%
\hskip 1em \@plus.17fil%
\begin{tabular}[t]{c}}% % \end{tabular}
So, when you write \author{First \and Second}, the result is that both names get typeset side-by-side in individual tabular environments. You could just as easily write \author{First \\ Second} to have the two names typeset in a column (that is, in the single centered column of the first tabular environment). The same could be done by redefining \and as \def\and{\\}; only through chance does simply writing \author{First & Second} do the same thing, as the "extra" alignment character, &, is interpreted as \\ automatically.
But this last approach will only work for you if you include something along the lines of the original author portion of \maketitle, that defines the tabular array in your own \maketitle.
Updated from OP Edit:
You can use \uppercase to do the uppercase translation in the following manner. As noted, I suggest you use the entire structure (with tabular) as originally defined in report.cls for the author portion in your own \maketitle. This keeps the original format with \and working, along with the other methods I mention above.
\documentclass{report}
\author{Doug \\ Lou}
\begin{document}
\makeatletter
\begin{center}
% Suggest using the tabular in your \maketitle definition
{\large
\lineskip .75em%
\begin{tabular}[t]{c}%
\uppercase\expandafter{\@author}
\end{tabular}\par}%
\end{center}
\makeatother
\end{document}
Best Answer
The
elsarticledocument class uses a comma to separate multiple authors; if you are using this document class, then I would advise you not to change the pre-stablished formatting; it was designed specifically to satisfy the requirements of Elsevier. However, if you decide to change the template, then you will need a redefinition of the internal\@authorcommand, as shown below (warning: will use "and" between all authors):